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4. Influence of sawtooth oscillations on fast ions in a stellarator

Author

Moseev, D., Zanini, M., Kasahara, H., Laqua, H.P., Funaba, H., Hayashi, W.H.J., Heidbrink, W., Ida, K., Igami, H., Kawamoto, Y., Kenmochi, N., Lazerson, S.A., Nishiura, M., Ochoukov, R., Ogawa, K., Rud, M., Salewski, M., Seki, T., Tamura, N., Tanaka, K., Tokuzawa, T., Yoshinuma, M., Moseev, D., Zanini, M., Kasahara, H., Laqua, H.P., Funaba, H., Hayashi, W.H.J., Heidbrink, W., Ida, K., Igami, H., Kawamoto, Y., Kenmochi, N., Lazerson, S.A., Nishiura, M., Ochoukov, R., Ogawa, K., Rud, M., Salewski, M., Seki, T., Tamura, N., Tanaka, K., Tokuzawa, T., and Yoshinuma, M.

Abstract

Sawtooth oscillations in tokamaks frequently lead to the redistribution of energetic ions, mainly on passing orbits, causing their expulsion from the core. This paper discusses the first measurements of the interaction of fast ions and sawteeth in the Large Helical Device. The crashes were caused by the plasma current induced by Electron Cyclotron Current Drive and Neutral Beam Current Drive. Despite these crashes, there was no detectable redistribution effect on fast ions in either the core or at the edge of the plasma.

Published
2024

6. Multi-hole coupling power monitor with tapered sub-waveguide for dual-frequency high-power gyrotron.

Author

Yanai, R., Takeuchi, T., Mizuno, Y., Yoshimura, Y., Nishiura, M., Igami, H., Takahashi, H., Tsujimura, T. Ii, and Kenmochi, N.

Subjects
DIRECTIONAL couplers, PLASMA confinement, ELECTRIC lines, MICROWAVE plasmas, POWER transmission, ELECTRON plasma, CYCLOTRON resonance
Abstract

In magnetically confined fusion plasmas, a gyrotron is an essential auxiliary heating device for generating and sustaining plasma through electron cyclotron resonance heating owing to its ability to generate high-power microwaves. Microwaves emitted from a gyrotron are often transmitted through waveguides, and the transmitted power is monitored by a power monitor with a multi-hole directional coupler at the miter bend of the transmission line. Recently, a high-power dual-frequency gyrotron has been installed and operated in the Large Helical Device. A power monitor with good sensitivity to multiple frequencies is required to monitor the power transmission of the different frequencies at the same transmission line. In order to realize the power monitor, which can couple with the multiple-frequency microwaves, we focused on a sub-waveguide shape in the power monitor and investigated the influence of the tapered sub-waveguide by conducting electromagnetic simulations using a simple model. We also performed the high-power test using a power monitor with a tapered sub-waveguide. The experimental result was different from the simulation, but enough receiving power was obtained at both 116 and 154 GHz. [ABSTRACT FROM AUTHOR]

Published
2023
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7. A reduced-turbulence regime in the Large Helical Device upon injection of low-Z materials powders.

Author

Nespoli, F., Tanaka, K., Masuzaki, S., Ashikawa, N., Shoji, M., Gilson, E.P., Lunsford, R., Oishi, T., Ida, K., Yoshinuma, M., Takemura, Y., Kinoshita, T., Motojima, G., Osakabe, M., Kenmochi, N., Kawamura, G., Suzuki, C., Nagy, A., Bortolon, A., and Pablant, N.A.

Subjects
PLASMA turbulence, ELECTRIC flux, PLASMA temperature, POWDERS, ELECTRIC fields, DATABASES
Abstract

Recently an improved confinement regime, characterized by reduced turbulent fluctuations has been observed in the Large Helical Device upon the injection of boron powder into the plasma (Nespoli et al 2022 Nat. Phys. 18 350–56). In this article, we report in more detail the experimental observations of increased plasma temperature and the decrease of turbulent fluctuations across the plasma cross section, on an extended database. In particular, we compare powders of different materials (B, C, BN), finding similar temperature improvement and turbulence response for the three cases. Modeling of the powder penetration into the plasma and of neoclassical electric field and fluxes support the interpretation of the experimental results. Additionally, we report evidence of the temperature improvement increasing with powder injection rates and decreasing for both increasing density and heating power. Though, plasma turbulence response varies depending on the initial conditions of the plasma, making it difficult to draw an inclusive description of the phenomenon. [ABSTRACT FROM AUTHOR]

Published
2023
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8. Gas fueling effect on plasma profile in Heliotron J

Author

Mizuuchi, T., Lee, H.Y., Mukai, K., Yamamoto, K., Kobayashi, S., Okada, H., Yamamoto, S., Ohshima, S., Zang, L., Nagasaki, K., Minami, T., Kagawa, T., Minami, T.Y., Mizuno, K., Wada, Y., Arai, S., Yashiro, H., Watada, H., Hashimoto, K., Kenmochi, N., Nagae, Y., Sha, M., Nakamura, Y.I., Kasajima, K., Nishino, N., Hosoi, K., Nakashima, Y., Nakamura, Y., Konoshima, S., and Sano, F.

Published
2013
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10. Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

W7-X Team, Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S. A., Brunner, K. J., Damm, H., Drevlak, M., Ford, O. P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., Hirsch, M., Höfel, U., Kazakov, Ye. O., Kleiber, R., Krychowiak, M., Kwak, S., Langenberg, A., Laqua, H. P., Neuner, U., Pablant, N. A., Pasch, E., Pavone, A., Pedersen, T. S., Rahbarnia, K., Schilling, J., Scott, E. R., Stange, T., Svensson, J., Thomsen, H., Turkin, Y., Warmer, F., Wolf, R. C., Zhang, D., Abramovic, I., Äkäslompolo, S., Alcusón, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., Bähner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., Böckenhoff, D., Böswirth, B., Böttger, L.-G., Borsuk, V., Boscary, J., Bosch, H.-S., Brakel, R., Brand, H., Brandt, C., Bräuer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Burhenn, R., Bussiahn, R., Buttenschön, B., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Molin, A. da, Silva, A. da, Pena, A. de la, Degenkolbe, S., Dhard, C. P., Dibon, M., Dinklage, A., Dittmar, T., Drewelow, P., Drews, P., Durodie, F., Edlund, E., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Gates, D., Geiger, B., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Grulke, O., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Killer, C., Kirschner, A., Klinger, T., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., Köchl, F., Kolesnichenko, Y., Könies, A., König, R., Kornejew, P., Koschinsky, J.-P., Köster, F., Krämer, M., Krampitz, R., Krämer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kurz, P. A., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lücke, A., Lumsdaine, A., Lutsenko, V., Maaßberg, H., Marchuk, O., Matthew, J. H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morisaki, T., Moseev, D., Murakami, S., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ölmanns, J., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfuß, D., Paqay, S., Pawelec, E., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Pölöskei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., Röhlinger, H., Romé, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., Sanchez, M., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schlüter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipliä, S., Slaby, C., Sleczka, M., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szabó, V., Szabolics, T., Szepesi, T., Szökefalvi-Nagy, Z., Tamura, N., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulipán, S., Unterberg, B., Vakulchyk, I., Valet, S., Vanó, L., Eeten, P. van, Milligen, B. van, Vuuren, A. J. van, Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Stechow, A. von, Vorköper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Wauters, T., Wegener, L., Weggen, J., Wegner, T., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., Zuin, M., W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, Applied Physics and Science Education, Science and Technology of Nuclear Fusion, Turbulence in Fusion Plasmas, and European Commission

Subjects
Magnetically Confined Plasmas, Tokamak, Design, Helias, Nuclear engineering, Magnetically confined plasmas, 01 natural sciences, 7. Clean energy, Article, Plasma physics, 010305 fluids & plasmas, law.invention, law, Physics::Plasma Physics, 0103 physical sciences, Nuclear fusion, 010306 general physics, Engineering & allied operations, Stellarator, Physics, Plasma fusion, Multidisciplinary, Toroid, biology, Plasma Physics, Física, Magnetic confinement fusion, Plasma, biology.organism_classification, Energía Nuclear, ddc:620, Wendelstein 7-X
Abstract

Research on magnetic confinement of high-temperature plasmas has the ultimate goal of harnessing nuclear fusion for the production of electricity. Although the tokamak1 is the leading toroidal magnetic-confinement concept, it is not without shortcomings and the fusion community has therefore also pursued alternative concepts such as the stellarator. Unlike axisymmetric tokamaks, stellarators possess a three-dimensional (3D) magnetic field geometry. The availability of this additional dimension opens up an extensive configuration space for computational optimization of both the field geometry itself and the current-carrying coils that produce it. Such an optimization was undertaken in designing Wendelstein 7-X (W7-X)2, a large helical-axis advanced stellarator (HELIAS), which began operation in 2015 at Greifswald, Germany. A major drawback of 3D magnetic field geometry, however, is that it introduces a strong temperature dependence into the stellarator’s non-turbulent ‘neoclassical’ energy transport. Indeed, such energy losses will become prohibitive in high-temperature reactor plasmas unless a strong reduction of the geometrical factor associated with this transport can be achieved; such a reduction was therefore a principal goal of the design of W7-X. In spite of the modest heating power currently available, W7-X has already been able to achieve high-temperature plasma conditions during its 2017 and 2018 experimental campaigns, producing record values of the fusion triple product for such stellarator plasmas3,4. The triple product of plasma density, ion temperature and energy confinement time is used in fusion research as a figure of merit, as it must attain a certain threshold value before net-energy-producing operation of a reactor becomes possible1,5. Here we demonstrate that such record values provide evidence for reduced neoclassical energy transport in W7-X, as the plasma profiles that produced these results could not have been obtained in stellarators lacking a comparably high level of neoclassical optimization., Previously documented record values of the fusion triple product in the stellarator Wendelstein 7-X are shown to be evidence for reduced neoclassical energy transport in this optimized device.

Published
2021

11. Publisher Correction: Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S. A., Brunner, K. J., Damm, H., Drevlak, M., Ford, O. P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., Hirsch, M., H��fel, U., Kazakov, Ye. O., Kleiber, R., Krychowiak, M., Kwak, S., Langenberg, A., Laqua, H. P., Neuner, U., Pablant, N. A., Pasch, E., Pavone, A., Pedersen, T. S., Rahbarnia, K., Schilling, J., Scott, E. R., Stange, T., Svensson, J., Thomsen, H., Turkin, Y., Warmer, F., Wolf, R. C., Zhang, D., Abramovic, I., ��k��slompolo, S., Alcus��n, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., B��hner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., B��ckenhoff, D., B��swirth, B., B��ttger, L.-G., Borsuk, V., Boscary, J., Bosch, H.-S., Brakel, R., Brand, H., Brandt, C., Br��uer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Burhenn, R., Bussiahn, R., Buttensch��n, B., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., De La Pena, A., Degenkolbe, S., Dhard, C. P., Dibon, M., Dinklage, A., Dittmar, T., Drewelow, P., Drews, P., Durodie, F., Edlund, E., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., Garc��a Rega��a, J., Gates, D., Geiger, B., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Grulke, O., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., H��lting, A., H��schen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Killer, C., Kirschner, A., Klinger, T., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., K��chl, F., Kolesnichenko, Y., K��nies, A., K��nig, R., Kornejew, P., Koschinsky, J.-P., K��ster, F., Kr��mer, M., Krampitz, R., Kr��mer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., K��hner, G., Kurki-Suonio, T., Kurz, P. A., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., L��cke, A., Lumsdaine, A., Lutsenko, V., Maa��berg, H., Marchuk, O., Matthew, J. H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., M��nnich, T., Morisaki, T., Moseev, D., Murakami, S., N��fr��di, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nocentini, R., N��hrenberg, C., N��hrenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., ��lmanns, J., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfu��, D., Paqay, S., Pawelec, E., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., P��l��skei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., R��csei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., R��hlinger, H., Rom��, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., S��nchez, E., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schl��ter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schr��der, M., Schr��der, T., Schroeder, R., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipli��, S., Slaby, C., Sleczka, M., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szab��, V., Szabolics, T., Szepesi, T., Sz��kefalvi-Nagy, Z., Tamura, N., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulip��n, S., Unterberg, B., Vakulchyk, I., Valet, S., Van��, L., Van Eeten, P., Van Milligen, B., Van Vuuren, A. J., Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Von Stechow, A., Vork��per, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Wauters, T., Wegener, L., Weggen, J., Wegner, T., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., and Zuin, M.

Subjects
Chemical engineering, ddc:660
Published
2021

14. Direct observation of the non-locality of non-diffusive counter-gradient electron thermal transport during the formation of hollow electron-temperature profiles in the Large Helical Device.

Author

Tsujimura, T. I., Kobayashi, T., Tanaka, K., Ida, K., Nagaoka, K., Yoshinuma, M., Yamada, I., Funaba, H., Seki, R., Satake, S., Kinoshita, T., Tokuzawa, T., Kenmochi, N., Igami, H., Mukai, K., Goto, M., and Kawamoto, Y.

Subjects
THERMAL electrons, ELECTRON transport, ELECTRON cyclotron resonance heating, TRANSPORT theory, POSITRONS
Abstract

A heating source with off-axis electron cyclotron heating (ECH) alone produced a plasma with a quasi-steady-state hollow electron-temperature profile in the Large Helical Device. The clear formation of this quasi-steady-state hollow electron-temperature profile can be explained by adding the outward heat convection term to the diffusion term, as a simple model to describe the electron heat flux, using the energy conservation equation. In addition, we directly observed the non-locality of the non-diffusive (convective) contribution in transient electron thermal transport in the condition that power-modulated on-axis ECH was applied to the plasma sustained by off-axis ECH. The experimentally evaluated flux-gradient relation shows two different positive values of the electron heat flux at zero temperature gradient by going back and forth between positive and negative temperature gradient regions in the transport hysteresis phenomenon. [ABSTRACT FROM AUTHOR]

Published
2022
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15. Study of detached plasma profile in the divertor simulation experimental module of tandem mirror GAMMA 10/PDX.

Author

Yoshikawa, M., Kohagura, J., Ezumi, N., Iijima, T., Nojiri, K., Terakado, A., Nakashima, Y., Kariya, T., Numakura, T., Hirata, M., Minami, R., Sakamoto, M., Ichimura, M., Islam, M. S., Shima, Y., Yasuhara, R., Yamada, I., Funaba, H., Minami, T., and Kenmochi, N.

Subjects
ELECTRON temperature measurement, PLASMA temperature, FUSION reactor divertors, PLASMA density, THOMSON scattering, ELECTRON temperature, ELECTRON density
Abstract

A divertor simulation experimental module (D-module) in the tandem mirror GAMMA 10/PDX was used for the study of plasma detachment. In previous studies, it was difficult to measure far-upstream plasma parameters in the D-module, and only electrostatic probes on the target plate were used to perform electron temperature and density measurements. To study the detached plasma structure, a Thomson scattering (TS) system and a microwave interferometer system have been installed to measure the inside plasma parameters of the D-module, and a movable electrostatic probe has been placed at the inlet of the D-module to measure the inlet plasma density and temperature. The TS system in the central cell observed the electron temperature and density of the core plasma simultaneously. These measurements revealed the entire density and temperature structure from the core plasma to the divertor plate. The line average electron density measured by the microwave interferometer showed a rollover behavior during detachment. The results indicated that the ionization region was located around the center of the D-module, and it appears to move upstream along the axis. [ABSTRACT FROM AUTHOR]

Published
2021
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17. Overview of first Wendelstein 7-X high-performance operation

Author

Klinger, T., Andreeva, T., Bozhenkov, S., Brandt, C., Burhenn, R., Buttenschön, B., Fuchert, G., Geiger, B., Grulke, O., Laqua, H., Pablant, N., Rahbarnia, K., Stange, T., von Stechow, A., Tamura, N., Thomsen, H., Turkin, Y., Wegner, T., Abramovic, I., Äkäslompolo, S., Alcuson, J., Aleynikov, P., Aleynikova, K., Ali, A., Alonso, A., Anda, G., Ascasibar, E., Bähner, J.P., Baek, S.G., Balden, M., Baldzuhn, J., Banduch, M., Barbui, T., Behr, W., Beidler, C., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., Böckenhoff, D., Böswirth, B., Böttger, L.-G., Borchardt, M., Borsuk, V., Boscary, J., Bosch, H.-S., Beurskens, M., Brakel, R., Brand, H., Bräuer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Bussiahn, R., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carralero, D., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M.J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., da Molin, A., da Silva, A., Damm, H., de la Pena, A., Degenkolbe, S., Dhard, C.P., Dibon, M., Dinklage, A., Dittmar, T., Drevlak, M., Drewelow, P., Drews, P., Durodie, F., Edlund, E., van Eeten, P., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W.H., Figacz, W., Fontdecaba, J., Ford, O., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Gates, D., Geiger, J., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Guerard, C., Hacker, P., Han, X., Harris, J.H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Helander, P., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hirsch, M., Hollfeld, K.P., Höfel, U., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kazakov, Y.O., Kenmochi, N., Killer, C., Kirschner, A., Kleiber, R., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., Köchl, F., Kolesnichenko, Y., Könies, A., König, R., Kornejew, P., Koschinsky, J.-P., Köster, F., Krämer, M., Krampitz, R., Krämer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Krychowiak, M., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kurz, P.A., Kwak, S., Landreman, M., Lang, P., Lang, R., Langenberg, A., Langish, S., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lücke, A., Lumsdaine, A., Lutsenko, V., Maaßberg, H., Marchuk, O., Matthew, J.H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morisaki, T., Moseev, D., Murakami, S., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Neuner, U., Ngo, T., Nicolai, D., Nielsen, S.K., Niemann, H., Nishizawa, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ölmanns, J., Ongena, J., Oosterbeek, J.W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfuß, D., Paqay, S., Pasch, E., Pavone, A., Pawelec, E., Pedersen, T.S., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Pölöskei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., Röhlinger, H., Romé, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., Sanchez, E., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schilling, J., Schlaich, A., Schlisio, G., Schluck, F., Schlüter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Scott, E., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipliä, S., Slaby, C., Sleczka, M., Smith, H., Spiess, W., Spong, D.A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Svensson, J., Szabó, V., Szabolics, T., Szepesi, T., Szökefalvi-Nagy, Z., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J.M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulipán, S., Unterberg, B., Vakulchyk, I., Valet, S., Vano, L., van Milligen, B., van Vuuren, A.J., Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Vorköper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Warmer, F., Wauters, T., Wegener, L., Weggen, J., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wolf, R.C., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, D., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., Zuin, M., Klinger, T., Andreeva, T., Bozhenkov, S., Brandt, C., Burhenn, R., Buttenschön, B., Fuchert, G., Geiger, B., Grulke, O., Laqua, H., Pablant, N., Rahbarnia, K., Stange, T., von Stechow, A., Tamura, N., Thomsen, H., Turkin, Y., Wegner, T., Abramovic, I., Äkäslompolo, S., Alcuson, J., Aleynikov, P., Aleynikova, K., Ali, A., Alonso, A., Anda, G., Ascasibar, E., Bähner, J.P., Baek, S.G., Balden, M., Baldzuhn, J., Banduch, M., Barbui, T., Behr, W., Beidler, C., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., Böckenhoff, D., Böswirth, B., Böttger, L.-G., Borchardt, M., Borsuk, V., Boscary, J., Bosch, H.-S., Beurskens, M., Brakel, R., Brand, H., Bräuer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Bussiahn, R., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carralero, D., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M.J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., da Molin, A., da Silva, A., Damm, H., de la Pena, A., Degenkolbe, S., Dhard, C.P., Dibon, M., Dinklage, A., Dittmar, T., Drevlak, M., Drewelow, P., Drews, P., Durodie, F., Edlund, E., van Eeten, P., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W.H., Figacz, W., Fontdecaba, J., Ford, O., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Gates, D., Geiger, J., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Guerard, C., Hacker, P., Han, X., Harris, J.H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Helander, P., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hirsch, M., Hollfeld, K.P., Höfel, U., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kazakov, Y.O., Kenmochi, N., Killer, C., Kirschner, A., Kleiber, R., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., Köchl, F., Kolesnichenko, Y., Könies, A., König, R., Kornejew, P., Koschinsky, J.-P., Köster, F., Krämer, M., Krampitz, R., Krämer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Krychowiak, M., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kurz, P.A., Kwak, S., Landreman, M., Lang, P., Lang, R., Langenberg, A., Langish, S., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lücke, A., Lumsdaine, A., Lutsenko, V., Maaßberg, H., Marchuk, O., Matthew, J.H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morisaki, T., Moseev, D., Murakami, S., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Neuner, U., Ngo, T., Nicolai, D., Nielsen, S.K., Niemann, H., Nishizawa, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ölmanns, J., Ongena, J., Oosterbeek, J.W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfuß, D., Paqay, S., Pasch, E., Pavone, A., Pawelec, E., Pedersen, T.S., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Pölöskei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., Röhlinger, H., Romé, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., Sanchez, E., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schilling, J., Schlaich, A., Schlisio, G., Schluck, F., Schlüter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Scott, E., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipliä, S., Slaby, C., Sleczka, M., Smith, H., Spiess, W., Spong, D.A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Svensson, J., Szabó, V., Szabolics, T., Szepesi, T., Szökefalvi-Nagy, Z., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J.M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulipán, S., Unterberg, B., Vakulchyk, I., Valet, S., Vano, L., van Milligen, B., van Vuuren, A.J., Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Vorköper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Warmer, F., Wauters, T., Wegener, L., Weggen, J., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wolf, R.C., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, D., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., and Zuin, M.

Abstract

The optimized superconducting stellarator device Wendelstein 7-X (with major radiusR = 5.5 m, minor radius a = 0.5 m, and 30 m3 plasma volume) restarted operation after the assembly of a graphite heat shield and 10 inertially cooled island divertor modules. This paper reports on the results from the first high-performance plasma operation. Glow discharge conditioning and ECRH conditioning discharges in helium turned out to be important for density and edge radiation control. Plasma densities of 1–4.5 × 1019 m−3 with central electron temperatures 5–10 keV were routinely achieved with hydrogen gas fueling, frequently terminated by a radiative collapse. In a first stage, plasma densities up to 1.4 × 1020 m−3 were reached with hydrogen pellet injection and helium gas fueling. Here, the ions are indirectly heated, and at a central density of 8 · 1019 m−3 a temperature of 3.4 keV with Te/Ti = 1 was transiently accomplished, which corresponds to nTi(0)τE = 6.4 × 1019 keV s m−3 with a peak diamagnetic energy of 1.1 MJ and volume-averaged normalized plasma pressure β = 1.2%. The routine access to high plasma densities was opened with boronization of the first wall. After boronization, the oxygen impurity content was reduced by a factor of 10, the carbon impurity content by a factor of 5. The reduced (edge) plasma radiation level gives routinely access to higher densities without radiation collapse, e.g. well above 1 × 1020 m−2 line integrated density and Te = Ti = 2 keV central temperatures at moderate ECRH power. Both X2 and O2 mode ECRH schemes were successfully applied. Core turbulence was measured with a phase contrast imaging diagnostic and suppression of turbulence during pellet injection was observed.

Published
2019

20. Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000

Author

Pedersen, T, Otte, M, Lazerson, S, Helander, P, Bozhenkov, S, Biedermann, C, Klinger, T, Wolf, R, Bosch, H, Abramovic, I, Akaslompolo, S, Aleynikov, P, Aleynikova, K, Ali, A, Alonso, A, Anda, G, Andreeva, T, Ascasibar, E, Baldzuhn, J, Banduch, M, Barbui, T, Beidler, C, Benndorf, A, Beurskens, M, Biel, W, Birus, D, Blackwell, B, Blanco, E, Blatzheim, M, Bluhm, T, Bockenhoff, D, Bolgert, P, Borchardt, M, Bottger, L, Brakel, R, Brandt, C, Brauer, T, Braune, H, Burhenn, R, Buttenschon, B, Bykov, V, Calvo, I, Cappa, A, Carls, A, De Carvalho, B, Castejon, F, Cianciosa, M, Cole, M, Costea, S, Cseh, G, Czarnecka, A, Dal Molin, A, De La Cal, E, De La Pena, A, Degenkolbe, S, Dhard, C, Dinklage, A, Dostal, M, Drevlak, M, Drewelow, P, Drews, P, Dudek, A, Durodie, F, Dzikowicka, A, Von Eeten, P, Effenberg, F, Endler, M, Erckmann, V, Estrada, T, Fahrenkamp, N, Fellinger, J, Feng, Y, Figacz, W, Ford, O, Fornal, T, Frerichs, H, Fuchert, G, Garcia-Munoz, M, Geiger, B, Geiger, J, Gierse, N, Gogoleva, A, Goncalves, B, Gradic, D, Grahl, M, Gross, S, Grote, H, Grulke, O, Guerard, C, Haas, M, Harris, J, Hartfuss, H, Hartmann, D, Hathiramani, D, Hein, B, Heirnich, S, Henneberg, S, Hennig, C, Hernandez, J, Hidalgo, C, Hidalgo, U, Hirsch, M, Hofel, U, Holbe, H, Holting, A, Houry, M, Huber, V, Ionita, C, Israeli, B, Jablonski, S, Jakubowski, M, Van Vuuren, A, Jenzsch, H, Kaczmarczyk, J, Kallmeyer, J, Kamionka, U, Kasahara, H, Kenmochi, N, Kernbichler, W, Killer, C, Kinna, D, Kleiber, R, Knauer, J, Kochl, F, Kocsis, G, Kolesnichenko, Y, Konies, A, Konig, R, Kornejew, P, Koster, F, Kramer-Flecken, A, Krampitz, R, Krawzyk, N, Kremeyer, T, Krychowiak, M, Ksiazek, I, Kubkowska, M, Kuhner, G, Kurki-Suonio, T, Kurz, P, Kuttler, K, Kwak, S, Landreman, M, Langenberg, A, Lapayese, F, Laqua, H, Laube, R, Laux, M, Lentz, H, Lewerentz, M, Liang, Y, Liu, S, Lobsien, J, Cisquella, J, Lopez-Bruna, D, Lore, J, Lorenz, A, Lui, S, Lutsenko, V, Maassberg, H, Maisano-Brown, J, Marchuk, O, Marrelli, L, Marsen, S, Marushchenko, N, Masuzaki, S, Mccarthy, K, Mcneely, P, Medina, F, Milojevic, D, Mishchenko, A, Missal, B, Mittelstaedt, J, Mollen, A, Moncada, V, Monnich, T, Moseev, D, Nagel, M, Naujoks, D, Neilson, G, Neubauer, O, Neuner, U, Ngo, T, Niemann, H, Nuhrenberg, C, Nuhrenberg, J, Ochando, M, Ogawa, K, Ongena, J, Oosterbeek, H, Pablant, N, Pacella, D, Pacios, L, Panadero, N, Pasch, E, Pastor, I, Pavone, A, Pawelec, E, Pedrosa, A, Perseo, V, Peterson, B, Pilopp, D, Pisano, F, Piulatti, M, Plunk, G, Preynas, M, Proll, J, Sitjes, A, Purps, F, Rack, M, Rahbarnia, K, Riemann, J, Risse, K, Rong, P, Rosenberger, J, Rudischhauser, L, Rummel, K, Rummel, T, Runov, A, Rust, N, Ryc, L, Saitoh, H, Satake, S, Schacht, J, Schmitz, O, Schmuck, S, Schneider, B, Schneider, M, Schneider, W, Schrittwieser, R, Schroder, M, Schroder, T, Schroder, R, Schumacher, H, Schweer, B, Seki, R, Sinha, P, Sipilae, S, Slaby, C, Smith, H, Sousa, J, Spring, A, Standley, B, Stange, T, Von Stechow, A, Stephey, L, Stoneking, M, Stridde, U, Suzuki, Y, Svensson, J, Szabolics, T, Szepesi, T, Thomsen, H, Travere, J, Traverso, P, Mora, H, Tsuchiya, H, Tsuijmura, T, Turkin, Y, Valet, S, Van Milligen, B, Vela, L, Velasco, J, Vergote, M, Vervier, M, Viebke, H, Vilbrandt, R, Von Thun, C, Wagner, F, Wang, E, Wang, N, Warmer, F, Wauters, T, Wegener, L, Wegner, T, Weir, G, Wendorf, J, Wenzel, U, Werner, A, Wie, Y, Wiegel, B, Wilde, F, Windisch, T, Winkler, M, Winters, V, Wright, A, Wurden, G, Xanthopoulos, P, Yamada, I, Yasuhara, R, Yokoyama, M, Zhang, D, Zilker, M, Zimbal, A, Zocco, A, Zoletnik, S, Pedersen T. S., Otte M., Lazerson S., Helander P., Bozhenkov S., Biedermann C., Klinger T., Wolf R. C., Bosch H. -S., Abramovic I., Akaslompolo S., Aleynikov P., Aleynikova K., Ali A., Alonso A., Anda G., Andreeva T., Ascasibar E., Baldzuhn J., Banduch M., Barbui T., Beidler C., Benndorf A., Beurskens M., Biel W., Birus D., Blackwell B., Blanco E., Blatzheim M., Bluhm T., Bockenhoff D., Bolgert P., Borchardt M., Bottger L. -G., Brakel R., Brandt C., Brauer T., Braune H., Burhenn R., Buttenschon B., Bykov V., Calvo I., Cappa A., Carls A., De Carvalho B. B., Castejon F., Cianciosa M., Cole M., Costea S., Cseh G., Czarnecka A., Dal Molin A., De La Cal E., De La Pena A., Degenkolbe S., Dhard C. P., Dinklage A., Dostal M., Drevlak M., Drewelow P., Drews P., Dudek A., Durodie F., Dzikowicka A., Von Eeten P., Effenberg F., Endler M., Erckmann V., Estrada T., Fahrenkamp N., Fellinger J., Feng Y., Figacz W., Ford O., Fornal T., Frerichs H., Fuchert G., Garcia-Munoz M., Geiger B., Geiger J., Gierse N., Gogoleva A., Goncalves B., Gradic D., Grahl M., Gross S., Grote H., Grulke O., Guerard C., Haas M., Harris J., Hartfuss H. -J., Hartmann D., Hathiramani D., Hein B., Heirnich S., Henneberg S., Hennig C., Hernandez J., Hidalgo C., Hidalgo U., Hirsch M., Hofel U., Holbe H., Holting A., Houry M., Huber V., Ionita C., Israeli B., Jablonski S., Jakubowski M., Van Vuuren A. J., Jenzsch H., Kaczmarczyk J., Kallmeyer J. -P., Kamionka U., Kasahara H., Kenmochi N., Kernbichler W., Killer C., Kinna D., Kleiber R., Knauer J., Kochl F., Kocsis G., Kolesnichenko Y., Konies A., Konig R., Kornejew P., Koster F., Kramer-Flecken A., Krampitz R., Krawzyk N., Kremeyer T., Krychowiak M., Ksiazek I., Kubkowska M., Kuhner G., Kurki-Suonio T., Kurz P., Kuttler K., Kwak S., Landreman M., Langenberg A., Lapayese F., Laqua H., Laqua H. -P., Laube R., Laux M., Lentz H., Lewerentz M., Liang Y., Liu S., Lobsien J. -F., Cisquella J. L., Lopez-Bruna D., Lore J., Lorenz A., Lui S., Lutsenko V., Maassberg H., Maisano-Brown J., Marchuk O., Marrelli L., Marsen S., Marushchenko N., Masuzaki S., McCarthy K., McNeely P., Medina F., Milojevic D., Mishchenko A., Missal B., Mittelstaedt J., Mollen A., Moncada V., Monnich T., Moseev D., Nagel M., Naujoks D., Neilson G. H., Neubauer O., Neuner U., Ngo T. -T., Niemann H., Nuhrenberg C., Nuhrenberg J., Ochando M., Ogawa K., Ongena J., Oosterbeek H., Pablant N., Pacella D., Pacios L., Panadero N., Pasch E., Pastor I., Pavone A., Pawelec E., Pedrosa A., Perseo V., Peterson B., Pilopp D., Pisano F., Piulatti M. E., Plunk G., Preynas M., Proll J., Sitjes A. P., Purps F., Rack M., Rahbarnia K., Riemann J., Risse K., Rong P., Rosenberger J., Rudischhauser L., Rummel K., Rummel T., Runov A., Rust N., Ryc L., Saitoh H., Satake S., Schacht J., Schmitz O., Schmuck S., Schneider B., Schneider M., Schneider W., Schrittwieser R., Schroder M., Schroder T., Schroder R., Schumacher H. W., Schweer B., Seki R., Sinha P., Sipilae S., Slaby C., Smith H., Sousa J., Spring A., Standley B., Stange T., Von Stechow A., Stephey L., Stoneking M., Stridde U., Suzuki Y., Svensson J., Szabolics T., Szepesi T., Thomsen H., Travere J. -M., Traverso P., Mora H. T., Tsuchiya H., Tsuijmura T., Turkin Y., Valet S., Van Milligen B., Vela L., Velasco J. -L., Vergote M., Vervier M., Viebke H., Vilbrandt R., Von Thun C. P., Wagner F., Wang E., Wang N., Warmer F., Wauters T., Wegener L., Wegner T., Weir G., Wendorf J., Wenzel U., Werner A., Wie Y., Wiegel B., Wilde F., Windisch T., Winkler M., Winters V., Wright A., Wurden G., Xanthopoulos P., Yamada I., Yasuhara R., Yokoyama M., Zhang D., Zilker M., Zimbal A., Zocco A., Zoletnik S., Pedersen, T, Otte, M, Lazerson, S, Helander, P, Bozhenkov, S, Biedermann, C, Klinger, T, Wolf, R, Bosch, H, Abramovic, I, Akaslompolo, S, Aleynikov, P, Aleynikova, K, Ali, A, Alonso, A, Anda, G, Andreeva, T, Ascasibar, E, Baldzuhn, J, Banduch, M, Barbui, T, Beidler, C, Benndorf, A, Beurskens, M, Biel, W, Birus, D, Blackwell, B, Blanco, E, Blatzheim, M, Bluhm, T, Bockenhoff, D, Bolgert, P, Borchardt, M, Bottger, L, Brakel, R, Brandt, C, Brauer, T, Braune, H, Burhenn, R, Buttenschon, B, Bykov, V, Calvo, I, Cappa, A, Carls, A, De Carvalho, B, Castejon, F, Cianciosa, M, Cole, M, Costea, S, Cseh, G, Czarnecka, A, Dal Molin, A, De La Cal, E, De La Pena, A, Degenkolbe, S, Dhard, C, Dinklage, A, Dostal, M, Drevlak, M, Drewelow, P, Drews, P, Dudek, A, Durodie, F, Dzikowicka, A, Von Eeten, P, Effenberg, F, Endler, M, Erckmann, V, Estrada, T, Fahrenkamp, N, Fellinger, J, Feng, Y, Figacz, W, Ford, O, Fornal, T, Frerichs, H, Fuchert, G, Garcia-Munoz, M, Geiger, B, Geiger, J, Gierse, N, Gogoleva, A, Goncalves, B, Gradic, D, Grahl, M, Gross, S, Grote, H, Grulke, O, Guerard, C, Haas, M, Harris, J, Hartfuss, H, Hartmann, D, Hathiramani, D, Hein, B, Heirnich, S, Henneberg, S, Hennig, C, Hernandez, J, Hidalgo, C, Hidalgo, U, Hirsch, M, Hofel, U, Holbe, H, Holting, A, Houry, M, Huber, V, Ionita, C, Israeli, B, Jablonski, S, Jakubowski, M, Van Vuuren, A, Jenzsch, H, Kaczmarczyk, J, Kallmeyer, J, Kamionka, U, Kasahara, H, Kenmochi, N, Kernbichler, W, Killer, C, Kinna, D, Kleiber, R, Knauer, J, Kochl, F, Kocsis, G, Kolesnichenko, Y, Konies, A, Konig, R, Kornejew, P, Koster, F, Kramer-Flecken, A, Krampitz, R, Krawzyk, N, Kremeyer, T, Krychowiak, M, Ksiazek, I, Kubkowska, M, Kuhner, G, Kurki-Suonio, T, Kurz, P, Kuttler, K, Kwak, S, Landreman, M, Langenberg, A, Lapayese, F, Laqua, H, Laube, R, Laux, M, Lentz, H, Lewerentz, M, Liang, Y, Liu, S, Lobsien, J, Cisquella, J, Lopez-Bruna, D, Lore, J, Lorenz, A, Lui, S, Lutsenko, V, Maassberg, H, Maisano-Brown, J, Marchuk, O, Marrelli, L, Marsen, S, Marushchenko, N, Masuzaki, S, Mccarthy, K, Mcneely, P, Medina, F, Milojevic, D, Mishchenko, A, Missal, B, Mittelstaedt, J, Mollen, A, Moncada, V, Monnich, T, Moseev, D, Nagel, M, Naujoks, D, Neilson, G, Neubauer, O, Neuner, U, Ngo, T, Niemann, H, Nuhrenberg, C, Nuhrenberg, J, Ochando, M, Ogawa, K, Ongena, J, Oosterbeek, H, Pablant, N, Pacella, D, Pacios, L, Panadero, N, Pasch, E, Pastor, I, Pavone, A, Pawelec, E, Pedrosa, A, Perseo, V, Peterson, B, Pilopp, D, Pisano, F, Piulatti, M, Plunk, G, Preynas, M, Proll, J, Sitjes, A, Purps, F, Rack, M, Rahbarnia, K, Riemann, J, Risse, K, Rong, P, Rosenberger, J, Rudischhauser, L, Rummel, K, Rummel, T, Runov, A, Rust, N, Ryc, L, Saitoh, H, Satake, S, Schacht, J, Schmitz, O, Schmuck, S, Schneider, B, Schneider, M, Schneider, W, Schrittwieser, R, Schroder, M, Schroder, T, Schroder, R, Schumacher, H, Schweer, B, Seki, R, Sinha, P, Sipilae, S, Slaby, C, Smith, H, Sousa, J, Spring, A, Standley, B, Stange, T, Von Stechow, A, Stephey, L, Stoneking, M, Stridde, U, Suzuki, Y, Svensson, J, Szabolics, T, Szepesi, T, Thomsen, H, Travere, J, Traverso, P, Mora, H, Tsuchiya, H, Tsuijmura, T, Turkin, Y, Valet, S, Van Milligen, B, Vela, L, Velasco, J, Vergote, M, Vervier, M, Viebke, H, Vilbrandt, R, Von Thun, C, Wagner, F, Wang, E, Wang, N, Warmer, F, Wauters, T, Wegener, L, Wegner, T, Weir, G, Wendorf, J, Wenzel, U, Werner, A, Wie, Y, Wiegel, B, Wilde, F, Windisch, T, Winkler, M, Winters, V, Wright, A, Wurden, G, Xanthopoulos, P, Yamada, I, Yasuhara, R, Yokoyama, M, Zhang, D, Zilker, M, Zimbal, A, Zocco, A, Zoletnik, S, Pedersen T. S., Otte M., Lazerson S., Helander P., Bozhenkov S., Biedermann C., Klinger T., Wolf R. C., Bosch H. -S., Abramovic I., Akaslompolo S., Aleynikov P., Aleynikova K., Ali A., Alonso A., Anda G., Andreeva T., Ascasibar E., Baldzuhn J., Banduch M., Barbui T., Beidler C., Benndorf A., Beurskens M., Biel W., Birus D., Blackwell B., Blanco E., Blatzheim M., Bluhm T., Bockenhoff D., Bolgert P., Borchardt M., Bottger L. -G., Brakel R., Brandt C., Brauer T., Braune H., Burhenn R., Buttenschon B., Bykov V., Calvo I., Cappa A., Carls A., De Carvalho B. B., Castejon F., Cianciosa M., Cole M., Costea S., Cseh G., Czarnecka A., Dal Molin A., De La Cal E., De La Pena A., Degenkolbe S., Dhard C. P., Dinklage A., Dostal M., Drevlak M., Drewelow P., Drews P., Dudek A., Durodie F., Dzikowicka A., Von Eeten P., Effenberg F., Endler M., Erckmann V., Estrada T., Fahrenkamp N., Fellinger J., Feng Y., Figacz W., Ford O., Fornal T., Frerichs H., Fuchert G., Garcia-Munoz M., Geiger B., Geiger J., Gierse N., Gogoleva A., Goncalves B., Gradic D., Grahl M., Gross S., Grote H., Grulke O., Guerard C., Haas M., Harris J., Hartfuss H. -J., Hartmann D., Hathiramani D., Hein B., Heirnich S., Henneberg S., Hennig C., Hernandez J., Hidalgo C., Hidalgo U., Hirsch M., Hofel U., Holbe H., Holting A., Houry M., Huber V., Ionita C., Israeli B., Jablonski S., Jakubowski M., Van Vuuren A. J., Jenzsch H., Kaczmarczyk J., Kallmeyer J. -P., Kamionka U., Kasahara H., Kenmochi N., Kernbichler W., Killer C., Kinna D., Kleiber R., Knauer J., Kochl F., Kocsis G., Kolesnichenko Y., Konies A., Konig R., Kornejew P., Koster F., Kramer-Flecken A., Krampitz R., Krawzyk N., Kremeyer T., Krychowiak M., Ksiazek I., Kubkowska M., Kuhner G., Kurki-Suonio T., Kurz P., Kuttler K., Kwak S., Landreman M., Langenberg A., Lapayese F., Laqua H., Laqua H. -P., Laube R., Laux M., Lentz H., Lewerentz M., Liang Y., Liu S., Lobsien J. -F., Cisquella J. L., Lopez-Bruna D., Lore J., Lorenz A., Lui S., Lutsenko V., Maassberg H., Maisano-Brown J., Marchuk O., Marrelli L., Marsen S., Marushchenko N., Masuzaki S., McCarthy K., McNeely P., Medina F., Milojevic D., Mishchenko A., Missal B., Mittelstaedt J., Mollen A., Moncada V., Monnich T., Moseev D., Nagel M., Naujoks D., Neilson G. H., Neubauer O., Neuner U., Ngo T. -T., Niemann H., Nuhrenberg C., Nuhrenberg J., Ochando M., Ogawa K., Ongena J., Oosterbeek H., Pablant N., Pacella D., Pacios L., Panadero N., Pasch E., Pastor I., Pavone A., Pawelec E., Pedrosa A., Perseo V., Peterson B., Pilopp D., Pisano F., Piulatti M. E., Plunk G., Preynas M., Proll J., Sitjes A. P., Purps F., Rack M., Rahbarnia K., Riemann J., Risse K., Rong P., Rosenberger J., Rudischhauser L., Rummel K., Rummel T., Runov A., Rust N., Ryc L., Saitoh H., Satake S., Schacht J., Schmitz O., Schmuck S., Schneider B., Schneider M., Schneider W., Schrittwieser R., Schroder M., Schroder T., Schroder R., Schumacher H. W., Schweer B., Seki R., Sinha P., Sipilae S., Slaby C., Smith H., Sousa J., Spring A., Standley B., Stange T., Von Stechow A., Stephey L., Stoneking M., Stridde U., Suzuki Y., Svensson J., Szabolics T., Szepesi T., Thomsen H., Travere J. -M., Traverso P., Mora H. T., Tsuchiya H., Tsuijmura T., Turkin Y., Valet S., Van Milligen B., Vela L., Velasco J. -L., Vergote M., Vervier M., Viebke H., Vilbrandt R., Von Thun C. P., Wagner F., Wang E., Wang N., Warmer F., Wauters T., Wegener L., Wegner T., Weir G., Wendorf J., Wenzel U., Werner A., Wie Y., Wiegel B., Wilde F., Windisch T., Winkler M., Winters V., Wright A., Wurden G., Xanthopoulos P., Yamada I., Yasuhara R., Yokoyama M., Zhang D., Zilker M., Zimbal A., Zocco A., and Zoletnik S.

Abstract

Fusion energy research has in the past 40 years focused primarily on the tokamak concept, but recent advances in plasma theory and computational power have led to renewed interest in stellarators. The largest and most sophisticated stellarator in the world, Wendelstein 7-X (W7-X), has just started operation, with the aim to show that the earlier weaknesses of this concept have been addressed successfully, and that the intrinsic advantages of the concept persist, also at plasma parameters approaching those of a future fusion power plant. Here we show the first physics results, obtained before plasma operation: that the carefully tailored topology of nested magnetic surfaces needed for good confinement is realized, and that the measured deviations are smaller than one part in 100,000. This is a significant step forward in stellarator research, since it shows that the complicated and delicate magnetic topology can be created and verified with the required accuracy.

Published
2016

21. Magnetic configuration effects on the Wendelstein 7-X stellarator

Author

Dinklage A., Beidler C.D., Helander P., Fuchert G., Maassberg H., Rahbarnia K., Sunn Pedersen T., Turkin Y., Wolf R.C., Alonso A., Andreeva T., Blackwell B., Bozhenkov S., Buttenschon B., Czarnecka A., Effenberg F., Feng Y., Geiger J., Hirsch M., Hofel U., Jakubowski M., Klinger T., Knauer J., Kocsis G., Kramer-Flecken A., Kubkowska M., Langenberg A., Laqua H.P., Marushchenko N., Mollen A., Neuner U., Niemann H., Pasch E., Pablant N., Rudischhauser L., Smith H.M., Schmitz O., Stange T., Szepesi T., Weir G., Windisch T., Wurden G.A., Zhang D., Abramovic I., Akaslompolo S., Ali A., Belloso J.A., Aleynikov P., Aleynikova K., Alzbutas R., Anda G., Ascasibar E., Assmann J., Baek S.-G., Baldzuhn J., Banduch M., Barbui T., Barlak M., Baumann K., Behr W., Beidler C., Benndorf A., Bertuch O., Beurskens M., Biedermann C., Biel W., Birus D., Blanco E., Blatzheim M., Bluhm T., Bockenhoff D., Bolgert P., Borchardt M., Borsuk V., Boscary J., Bosch H.-S., Bottger L.-G., Brakel R., Brand H., Brandt C., Brauer T., Braune H., Brezinsek S., Brunner K.-J., Brunner B., Burhenn R., Bussiahn R., Bykov V., Cai Y., Calvo I., Cannas B., Cappa A., Card A., Carls A., Carraro L., Carvalho B., Castejon F., Charl A., Chernyshev F., Cianciosa M., Citarella R., Ciupinski L., Claps G., Cole M.J., Cordella F., Cseh G., Czermak A., Czerski K., Czerwinski M., Czymek G., da Molin A., da Silva A., Dammertz G., de la Pena A., Degenkolbe S., Denner P., Dittmar T., Dhard C.P., Dostal M., Drevlak M., Drewelow P., Drews P., Dudek A., Dundulis G., Durodie F., van Eeten P., Ehrke G., Endler M., Ennis D., Erckmann E., Esteban H., Estrada T., Fahrenkamp N., Feist J.-H., Fellinger J., Fernandes H., Fietz W.H., Figacz W., Fontdecaba J., Ford O., Fornal T., Frerichs H., Freund A., Fuhrer M., Funaba T., Galkowski A., Gantenbein G., Gao Y., Regana J.G., Garcia-Munoz M., Gates D., Gawlik G., Geiger B., Giannella V., Gierse N., Gogoleva A., Goncalves B., Goriaev A., Gradic D., Grahl M., Green J., Grosman A., Grote H., Gruca M., Grulke O., Guerard C., Hacker P., Haiduk L., Hammond K., Han X., Harberts F., Harris J.H., Hartfuss H.-J., Hartmann D., Hathiramani D., Hein B., Heinemann B., Heitzenroeder P., Henneberg S., Hennig C., Sanchez J.H., Hidalgo C., Holbe H., Hollfeld K.P., Holting A., Hoschen D., Houry M., Howard J., Huang X., Huber M., Huber V., Hunger H., Ida K., Ilkei T., Illy S., Israeli B., Ivanov A., Jablonski S., Jagielski J., Jelonnek J., Jenzsch H., Junghans P., Kacmarczyk J., Kaliatka T., Kallmeyer J.-P., Kamionka U., Karalevicius R., Kasahara H., Kasparek W., Kazakov Y., Kenmochi N., Keunecke M., Khilchenko A., Killer C., Kinna D., Kleiber R., Knaup M., Knieps A., Kobarg T., Kochl F., Kolesnichenko Y., Konies A., Koppen M., Koshurinov J., Koslowski R., Konig R., Koster F., Kornejew P., Koziol R., Kramer M., Krampitz R., Kraszewsk P., Krawczyk N., Kremeyer T., Krings T., Krom J., Krychowiak M., Krzesinski G., Ksiazek I., Kuhner G., Kurki-Suonio T., Kwak S., Landreman M., Lang R., Langish S., Laqua H., Laube R., Lazerson S., Lechte C., Lennartz M., Leonhardt W., Lewerentz L., Liang Y., Linsmeier C., Liu S., Lobsien J.-F., Loesser D., Cisquella J.L., Lore J., Lorenz A., Losert M., Lubyako L., Lucke A., Lumsdaine A., Lutsenko V., Maisano-Brown J., Marchuk O., Mardenfeld M., Marek P., Marsen S., Marushchenko M., Masuzaki S., Maurer D., McCarthy K., McNeely P., Meier A., Mellein D., Mendelevitch B., Mertens P., Mikkelsen D., Mishchenko O., Missal B., Mittelstaedt J., Mizuuchi T., Moncada V., Monnich T., Morisaki T., Moseev D., Munk R., Murakami S., Musielok F., Nafradi G., Nagel M., Naujoks D., Neilson H., Neubauer O., Ngo T., Nocentini R., Nuhrenberg C., Nuhrenberg J., Obermayer S., Offermanns G., Ogawa K., Ongena J., Oosterbeek J.W., Orozco G., Otte M., Rodriguez L.P., Pan W., Panadero N., Alvarez N.P., Panin A., Papenfuss D., Paqay S., Pavone A., Pawelec E., Pelka G., Peng X., Perseo V., Peterson B., Pieper A., Pilopp D., Pingel S., Pisano F., Plaum B., Plunk G., Povilaitis M., Preinhaelter J., Proll J., Puiatti M.-E., Sitjes A.P., Purps F., Rack M., Recsei S., Reiman A., Reiter D., Remppel F., Renard S., Riedl R., Riemann J., Rimkevicius S., Risse K., Rodatos A., Rohlinger H., Rome M., Rong P., Roscher H.-J., Roth B., Rummel K., Rummel T., Runov A., Rust N., Ryc L., Ryosuke S., Sakamoto R., Samartsev A., Sanchez M., Sano F., Satake S., Satheeswaran G., Schacht J., Schauer F., Scherer T., Schlaich A., Schlisio G., Schluter K.-H., Schmitt J., Schmitz H., Schmuck S., Schneider M., Schneider W., Scholz M., Scholz P., Schrittwieser R., Schroder M., Schroder T., Schroeder R., Schumacher H., Schweer B., Shanahan B., Shikhovtsev I.V., Sibilia M., Sinha P., Siplia S., Skodzik J., Slaby C., Smith H., Spiess W., Spong D.A., Spring A., Stadler R., Standley B., Stephey L., Stoneking M., Stridde U., Sulek Z., Pedersen T.S., Suzuki Y., Svensson J., Szabo V., Szabolics T., Szokefalvi-Nagy Z., Tamura N., Terra A., Terry J., Thomas J., Thomsen H., Thumm M., von Thun C.P., Timmermann D., Titus P., Toi K., Travere J.M., Traverso P., Tretter J., Mora H.T., Tsuchiya H., Tsujimura T., Tulipan S., Turnyanskiy M., Unterberg B., Urban J., Urbonavicius E., Vakulchyk I., Valet S., van Milligen B., Vela L., Velasco J.-L., Vergote M., Vervier M., Vianello N., Viebke H., Vilbrandt R., Vorkorper A., Wadle S., Wang E., Wang N., Warmer F., Wauters T., Wegener L., Weggen J., Wegner T., Wei Y., Wendorf J., Wenzel U., Wiegel B., Wilde F., Winkler E., Winters V., Wolf R., Wolf S., Wolowski J., Wright A., Wurden G., Xanthopoulos P., Yamada H., Yamada I., Yasuhara R., Yokoyama M., Zajac J., Zarnstorff M., Zeitler A., Zhang H., Zhu J., Zilker M., Zimbal A., Zocco A., Zoletnik S., Zuin M., W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, Science and Technology of Nuclear Fusion, and Turbulence in Fusion Plasmas

Subjects
Physics, Tokamak, Field (physics), General Physics and Astronomy, Plasma, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, Bootstrap current, Computational physics, Magnetic field, law.invention, Magnetic mirror, Wendelstein 7-X stellarator, Physics and Astronomy (all), law, Physics::Plasma Physics, 0103 physical sciences, Wendelstein 7-X plasmas, Wendelstein 7-X, 010306 general physics, Stellarator
Abstract

The two leading concepts for confining high-temperature fusion plasmas are the tokamak and the stellarator. Tokamaks are rotationally symmetric and use a large plasma current to achieve confinement, whereas stellarators are non-axisymmetric and employ three-dimensionally shaped magnetic field coils to twist the field and confine the plasma. As a result, the magnetic field of a stellarator needs to be carefully designed to minimize the collisional transport arising from poorly confined particle orbits, which would otherwise cause excessive power losses at high plasma temperatures. In addition, this type of transport leads to the appearance of a net toroidal plasma current, the so-called bootstrap current. Here, we analyse results from the first experimental campaign of the Wendelstein 7-X stellarator, showing that its magnetic-field design allows good control of bootstrap currents and collisional transport. The energy confinement time is among the best ever achieved in stellarators, both in absolute figures (τE > 100 ms) and relative to the stellarator confinement scaling. The bootstrap current responds as predicted to changes in the magnetic mirror ratio. These initial experiments confirm several theoretically predicted properties of Wendelstein 7-X plasmas, and already indicate consistency with optimization measures. Results from the first experimental campaign of the Wendelstein 7-X stellarator demonstrate that its magnetic-field design grants good control of parasitic plasma currents, leading to long energy confinement times.

Published
2018

22. Improvement in multipass Thomson scattering system comprising laser amplification system developed in GAMMA 10/PDX.

Author

Yoshikawa, M., Mouri, T., Nakanishi, H., Kohagura, J., Shima, Y., Sakamoto, M., Nakashima, Y., Ezumi, N., Minami, R., Yamada, I., Yasuhara, R., Funaba, H., Minami, T., and Kenmochi, N.

Subjects
THOMSON scattering, LASERS, LASER beams, OPTICS
Abstract

The multipass Thomson scattering (MPTS) technique is one of the most useful methods for measuring low-electron-density plasmas. The MPTS system increases Thomson scattering (TS) signal intensities by integrating all multipass (MP) signals and improving the TS time resolution by analyzing each pass signal. The fully coaxial MPTS system developed in GAMMA 10/potential-control and diverter–simulator experiments has a polarization-based configuration with image-relaying optics. The MPTS system can enhance Thomson scattered signals for improving the measurement accuracy and megahertz-order time resolution. In this study, we develop a new MPTS system comprising a laser amplification system to obtain continuous MP signals. The laser amplification system can improve degraded laser power and return an amplified laser to the MP system. We obtain continuous MP signals from the laser amplification system by improving the laser beam profile adjuster in gas scattering experiments. Moreover, we demonstrate that more MP signals and stronger amplified MP signals can be achieved via multiple laser injections to the laser amplification system in the developed MP system comprising a laser amplification system. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
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23. Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000

Author

Pedersen T. S., Otte M., Lazerson S., Helander P., Bozhenkov S., Biedermann C., Klinger T., Wolf R. C., Bosch H. -S., Abramovic I., Akaslompolo S., Aleynikov P., Aleynikova K., Ali A., Alonso A., Anda G., Andreeva T., Ascasibar E., Baldzuhn J., Banduch M., Barbui T., Beidler C., Benndorf A., Beurskens M., Biel W., Birus D., Blackwell B., Blanco E., Blatzheim M., Bluhm T., Bockenhoff D., Bolgert P., Borchardt M., Bottger L. -G., Brakel R., Brandt C., Brauer T., Braune H., Burhenn R., Buttenschon B., Bykov V., Calvo I., Cappa A., Carls A., De Carvalho B. B., Castejon F., Cianciosa M., Cole M., Costea S., Cseh G., Czarnecka A., Dal Molin A., De La Cal E., De La Pena A., Degenkolbe S., Dhard C. P., Dinklage A., Dostal M., Drevlak M., Drewelow P., Drews P., Dudek A., Durodie F., Dzikowicka A., Von Eeten P., Effenberg F., Endler M., Erckmann V., Estrada T., Fahrenkamp N., Fellinger J., Feng Y., Figacz W., Ford O., Fornal T., Frerichs H., Fuchert G., Garcia-Munoz M., Geiger B., Geiger J., Gierse N., Gogoleva A., Goncalves B., Gradic D., Grahl M., Gross S., Grote H., Grulke O., Guerard C., Haas M., Harris J., Hartfuss H. -J., Hartmann D., Hathiramani D., Hein B., Heirnich S., Henneberg S., Hennig C., Hernandez J., Hidalgo C., Hidalgo U., Hirsch M., Hofel U., Holbe H., Holting A., Houry M., Huber V., Ionita C., Israeli B., Jablonski S., Jakubowski M., Van Vuuren A. J., Jenzsch H., Kaczmarczyk J., Kallmeyer J. -P., Kamionka U., Kasahara H., Kenmochi N., Kernbichler W., Killer C., Kinna D., Kleiber R., Knauer J., Kochl F., Kocsis G., Kolesnichenko Y., Konies A., Konig R., Kornejew P., Koster F., Kramer-Flecken A., Krampitz R., Krawzyk N., Kremeyer T., Krychowiak M., Ksiazek I., Kubkowska M., Kuhner G., Kurki-Suonio T., Kurz P., Kuttler K., Kwak S., Landreman M., Langenberg A., Lapayese F., Laqua H., Laqua H. -P., Laube R., Laux M., Lentz H., Lewerentz M., Liang Y., Liu S., Lobsien J. -F., Cisquella J. L., Lopez-Bruna D., Lore J., Lorenz A., Lui S., Lutsenko V., Maassberg H., Maisano-Brown J., Marchuk O., Marrelli L., Marsen S., Marushchenko N., Masuzaki S., McCarthy K., McNeely P., Medina F., Milojevic D., Mishchenko A., Missal B., Mittelstaedt J., Mollen A., Moncada V., Monnich T., Moseev D., Nagel M., Naujoks D., Neilson G. H., Neubauer O., Neuner U., Ngo T. -T., Niemann H., Nuhrenberg C., Nuhrenberg J., Ochando M., Ogawa K., Ongena J., Oosterbeek H., Pablant N., Pacella D., Pacios L., Panadero N., Pasch E., Pastor I., Pavone A., Pawelec E., Pedrosa A., Perseo V., Peterson B., Pilopp D., Pisano F., Piulatti M. E., Plunk G., Preynas M., Proll J., Sitjes A. P., Purps F., Rack M., Rahbarnia K., Riemann J., Risse K., Rong P., Rosenberger J., Rudischhauser L., Rummel K., Rummel T., Runov A., Rust N., Ryc L., Saitoh H., Satake S., Schacht J., Schmitz O., Schmuck S., Schneider B., Schneider M., Schneider W., Schrittwieser R., Schroder M., Schroder T., Schroder R., Schumacher H. W., Schweer B., Seki R., Sinha P., Sipilae S., Slaby C., Smith H., Sousa J., Spring A., Standley B., Stange T., Von Stechow A., Stephey L., Stoneking M., Stridde U., Suzuki Y., Svensson J., Szabolics T., Szepesi T., Thomsen H., Travere J. -M., Traverso P., Mora H. T., Tsuchiya H., Tsuijmura T., Turkin Y., Valet S., Van Milligen B., Vela L., Velasco J. -L., Vergote M., Vervier M., Viebke H., Vilbrandt R., Von Thun C. P., Wagner F., Wang E., Wang N., Warmer F., Wauters T., Wegener L., Wegner T., Weir G., Wendorf J., Wenzel U., Werner A., Wie Y., Wiegel B., Wilde F., Windisch T., Winkler M., Winters V., Wright A., Wurden G., Xanthopoulos P., Yamada I., Yasuhara R., Yokoyama M., Zhang D., Zilker M., Zimbal A., Zocco A., Zoletnik S., W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, Massachusetts Institute of Technology. Department of Physics, Maisano-Brown, Jeannette D., Science and Technology of Nuclear Fusion, Pedersen, T, Otte, M, Lazerson, S, Helander, P, Bozhenkov, S, Biedermann, C, Klinger, T, Wolf, R, Bosch, H, Abramovic, I, Akaslompolo, S, Aleynikov, P, Aleynikova, K, Ali, A, Alonso, A, Anda, G, Andreeva, T, Ascasibar, E, Baldzuhn, J, Banduch, M, Barbui, T, Beidler, C, Benndorf, A, Beurskens, M, Biel, W, Birus, D, Blackwell, B, Blanco, E, Blatzheim, M, Bluhm, T, Bockenhoff, D, Bolgert, P, Borchardt, M, Bottger, L, Brakel, R, Brandt, C, Brauer, T, Braune, H, Burhenn, R, Buttenschon, B, Bykov, V, Calvo, I, Cappa, A, Carls, A, De Carvalho, B, Castejon, F, Cianciosa, M, Cole, M, Costea, S, Cseh, G, Czarnecka, A, Dal Molin, A, De La Cal, E, De La Pena, A, Degenkolbe, S, Dhard, C, Dinklage, A, Dostal, M, Drevlak, M, Drewelow, P, Drews, P, Dudek, A, Durodie, F, Dzikowicka, A, Von Eeten, P, Effenberg, F, Endler, M, Erckmann, V, Estrada, T, Fahrenkamp, N, Fellinger, J, Feng, Y, Figacz, W, Ford, O, Fornal, T, Frerichs, H, Fuchert, G, Garcia-Munoz, M, Geiger, B, Geiger, J, Gierse, N, Gogoleva, A, Goncalves, B, Gradic, D, Grahl, M, Gross, S, Grote, H, Grulke, O, Guerard, C, Haas, M, Harris, J, Hartfuss, H, Hartmann, D, Hathiramani, D, Hein, B, Heirnich, S, Henneberg, S, Hennig, C, Hernandez, J, Hidalgo, C, Hidalgo, U, Hirsch, M, Hofel, U, Holbe, H, Holting, A, Houry, M, Huber, V, Ionita, C, Israeli, B, Jablonski, S, Jakubowski, M, Van Vuuren, A, Jenzsch, H, Kaczmarczyk, J, Kallmeyer, J, Kamionka, U, Kasahara, H, Kenmochi, N, Kernbichler, W, Killer, C, Kinna, D, Kleiber, R, Knauer, J, Kochl, F, Kocsis, G, Kolesnichenko, Y, Konies, A, Konig, R, Kornejew, P, Koster, F, Kramer-Flecken, A, Krampitz, R, Krawzyk, N, Kremeyer, T, Krychowiak, M, Ksiazek, I, Kubkowska, M, Kuhner, G, Kurki-Suonio, T, Kurz, P, Kuttler, K, Kwak, S, Landreman, M, Langenberg, A, Lapayese, F, Laqua, H, Laube, R, Laux, M, Lentz, H, Lewerentz, M, Liang, Y, Liu, S, Lobsien, J, Cisquella, J, Lopez-Bruna, D, Lore, J, Lorenz, A, Lui, S, Lutsenko, V, Maassberg, H, Maisano-Brown, J, Marchuk, O, Marrelli, L, Marsen, S, Marushchenko, N, Masuzaki, S, Mccarthy, K, Mcneely, P, Medina, F, Milojevic, D, Mishchenko, A, Missal, B, Mittelstaedt, J, Mollen, A, Moncada, V, Monnich, T, Moseev, D, Nagel, M, Naujoks, D, Neilson, G, Neubauer, O, Neuner, U, Ngo, T, Niemann, H, Nuhrenberg, C, Nuhrenberg, J, Ochando, M, Ogawa, K, Ongena, J, Oosterbeek, H, Pablant, N, Pacella, D, Pacios, L, Panadero, N, Pasch, E, Pastor, I, Pavone, A, Pawelec, E, Pedrosa, A, Perseo, V, Peterson, B, Pilopp, D, Pisano, F, Piulatti, M, Plunk, G, Preynas, M, Proll, J, Sitjes, A, Purps, F, Rack, M, Rahbarnia, K, Riemann, J, Risse, K, Rong, P, Rosenberger, J, Rudischhauser, L, Rummel, K, Rummel, T, Runov, A, Rust, N, Ryc, L, Saitoh, H, Satake, S, Schacht, J, Schmitz, O, Schmuck, S, Schneider, B, Schneider, M, Schneider, W, Schrittwieser, R, Schroder, M, Schroder, T, Schroder, R, Schumacher, H, Schweer, B, Seki, R, Sinha, P, Sipilae, S, Slaby, C, Smith, H, Sousa, J, Spring, A, Standley, B, Stange, T, Von Stechow, A, Stephey, L, Stoneking, M, Stridde, U, Suzuki, Y, Svensson, J, Szabolics, T, Szepesi, T, Thomsen, H, Travere, J, Traverso, P, Mora, H, Tsuchiya, H, Tsuijmura, T, Turkin, Y, Valet, S, Van Milligen, B, Vela, L, Velasco, J, Vergote, M, Vervier, M, Viebke, H, Vilbrandt, R, Von Thun, C, Wagner, F, Wang, E, Wang, N, Warmer, F, Wauters, T, Wegener, L, Wegner, T, Weir, G, Wendorf, J, Wenzel, U, Werner, A, Wie, Y, Wiegel, B, Wilde, F, Windisch, T, Winkler, M, Winters, V, Wright, A, Wurden, G, Xanthopoulos, P, Yamada, I, Yasuhara, R, Yokoyama, M, Zhang, D, Zilker, M, Zimbal, A, Zocco, A, Zoletnik, S, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Department of Applied Physics, Aalto-yliopisto, Aalto University, and Pacella, D.

Subjects
Tokamak, Plasma parameters, Science, General Physics and Astronomy, Topology (electrical circuits), Topology, 7. Clean energy, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, 010305 fluids & plasmas, law.invention, law, 0103 physical sciences, 010306 general physics, Physics, Fusion, Wendelstein7-X, Stellarator, Multidisciplinary, ta114, General Chemistry, Plasma, Fusion power, Magnetic field, Erratum, Wendelstein 7-X, Stellarator
Abstract

Fusion energy research has in the past 40 years focused primarily on the tokamak concept, but recent advances in plasma theory and computational power have led to renewed interest in stellarators. The largest and most sophisticated stellarator in the world, Wendelstein 7-X (W7-X), has just started operation, with the aim to show that the earlier weaknesses of this concept have been addressed successfully, and that the intrinsic advantages of the concept persist, also at plasma parameters approaching those of a future fusion power plant. Here we show the first physics results, obtained before plasma operation: that the carefully tailored topology of nested magnetic surfaces needed for good confinement is realized, and that the measured deviations are smaller than one part in 100,000. This is a significant step forward in stellarator research, since it shows that the complicated and delicate magnetic topology can be created and verified with the required accuracy., Early stellarator designs suffered from high particle losses, an issue that can be addressed by optimization of the coils. Here the authors measure the magnetic field lines in the Wendelstein 7-X stellarator, confirming that the complicated design of the superconducting coils has been realized successfully.

Published
2016

24. Performance of Wendelstein 7-X stellarator plasmas during the first divertor operation phase

Author

Wolf, R. C., Alonso, A., Akaslompolo, S., Baldzuhn, J., Beurskens, M., Beidler, C. D., Biedermann, C., Bosch, H. -S., Bozhenkov, S., Brakel, R., Braune, H., Brezinsek, S., Brunner, K. -J., Damm, H., Dinklage, A., Drewelow, P., Effenberg, F., Feng, Y., Ford, O., Fuchert, G., Gao, Y., Geiger, J., Grulke, O., Harder, N., Hartmann, D., Helander, P., Heinemann, B., Hirsch, M., Hofel, U., Hopf, C., Ida, K., Isobe, M., Jakubowski, M. W., Kazakov, Y. O., Killer, C., Klinger, T., Knauer, J., Konig, R., Krychowiak, M., Langenberg, A., Laqua, H. P., Lazerson, S., Mcneely, P., Marsen, S., Marushchenko, N., Nocentini, R., Ogawa, K., Orozco, G., Osakabe, M., Otte, M., Pablant, N., Pasch, E., Pavone, A., Porkolab, M., Puig Sitjes, A., Rahbarnia, K., Riedl, R., Rust, N., Scott, E., Schilling, J., Schroeder, R., Stange, T., Von Stechow, A., Strumberger, E., Sunn Pedersen, T., Svensson, J., Thomson, H., Turkin, Y., Vano, L., Wauters, T., Wurden, G., Yoshinuma, M., Zanini, M., Zhang, D., Andreeva, T., Brandt, C., Burhenn, R., Buttenschon, B., Geiger, B., Tamura, N., Thomsen, H., Wegner, T., Abramovic, I., Alcuson, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., Bahner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Beidler, C., Benndorf, A., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., Bockenhoff, D., Boswirth, B., Bottger, L. -G., Borchardt, M., Borsuk, V., Boscary, J., Brand, H., Brauer, T., Bussiahn, R., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carralero, D., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., De La Pena, A., Degenkolbe, S., Dhard, C. P., Dibon, M., Dittmar, T., Drevlak, M., Drews, P., Durodie, F., Edlund, E., Van Eeten, P., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Garcia Regana, J., Gates, D., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hathiramani, D., Hein, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., Holting, A., Hoschen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J. -P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Kirschner, A., Kleiber, R., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., Kochl, F., Kolesnichenko, Y., Konies, A., Kornejew, P., Koschinsky, J. -P., Koster, F., Kramer, M., Krampitz, R., Kramer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., Kuhner, G., Kurki-Suonio, T., Kurz, P. A., Kwak, S., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J. -F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lucke, A., Lumsdaine, A., Lutsenko, V., Maassberg, H., Marchuk, O., Matthew, J. H., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., Mccarthy, K., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Monnich, T., Morisaki, T., Moseev, D., Murakami, S., Nafradi, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Neuner, U., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nuhrenberg, C., Nuhrenberg, J., Obermayer, S., Offermanns, G., Olmanns, J., Ongena, J., Oosterbeek, J. W., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfuss, D., Paqay, S., Pawelec, E., Pedersen, T. S., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Poloskei, P., Proll, J., Puiatti, M. -E., Purps, F., Rack, M., Recsei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riemann, J., Risse, K., Rohde, V., Rohlinger, H., Rome, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., Sanchez, E., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schluter, K. -H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schroder, M., Schroder, T., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Siplia, S., Slaby, C., Sleczka, M., Smith, H., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szabo, V., Szabolics, T., Szepesi, T., Szokefalvi-Nagy, Z., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulipan, S., Unterberg, B., Vakulchyk, I., Valet, S., Van Milligen, B., Van Vuuren, A. J., Vela, L., Velasco, J. -L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Vorkoper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Warmer, F., Wegener, L., Weggen, J., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., Zuin, M., Science and Technology of Nuclear Fusion, Turbulence in Fusion Plasmas, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Technology, Plasma parameters, Divertor, Nuclear engineering, Plasma, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, Electron cyclotron resonance, 010305 fluids & plasmas, law.invention, Magnetic field, law, 0103 physical sciences, Limiter, Wendelstein 7-X, 010306 general physics, ddc:600, Stellarator
Abstract

Wendelstein 7-X is the first comprehensively optimized stellarator aiming at good confinement with plasma parameters relevant to a future stellarator power plant. Plasma operation started in 2015 using a limiter configuration. After installing an uncooled magnetic island divertor, extending the energy limit from 4 to 80 MJ, operation continued in 2017. For this phase, the electron cyclotron resonance heating (ECRH) capability was extended to 7 MW, and hydrogen pellet injection was implemented. The enhancements resulted in the highest triple product (6.5 × 1019 keV m-3 s) achieved in a stellarator until now. Plasma conditions [Te(0) ≈ Ti(0) ≈ 3.8 keV, τE > 200 ms] already were in the stellarator reactor-relevant ion-root plasma transport regime. Stable operation above the 2nd harmonic ECRH X-mode cutoff was demonstrated, which is instrumental for achieving high plasma densities in Wendelstein 7-X. Further important developments include the confirmation of low intrinsic error fields, the observation of current-drive induced instabilities, and first fast ion heating and confinement experiments. The efficacy of the magnetic island divertor was instrumental in achieving high performance in Wendelstein 7-X. Symmetrization of the heat loads between the ten divertor modules could be achieved by external resonant magnetic fields. Full divertor power detachment facilitated the extension of high power plasmas significantly beyond the energy limit of 80 MJ.

Published
2019

25. Study of seed plasma generation for NBI plasma start-up using non-resonant microwave launch in Heliotron J.

Author

Kobayashi, S, Nagasaki, K, Stange, T, Mizuuchi, T, Okada, H, Minami, T, Kado, S, Yamamoto, S, Ohshima, S, Hada, K, Weir, G, Konoshima, S, Nakamura, Y, Kenmochi, N, Otani, Y, Lu, X X, Panith, A, Toi, K, and Suzuki, Y

Subjects
PLASMA production, PLASMA beam injection heating, ELECTRON impact ionization, MICROWAVE plasmas, SYNCHROTRON radiation, RELATIVISTIC electrons, MICROWAVES
Abstract

Here, we report on a study of seed plasmas produced by non-resonant 2.45 GHz microwave heating in Heliotron J, which is useful for plasma start-up by neutral beam injection (NBI) under the conditions of low beam power (<1 MW), low accerelation voltage (<30 kV) and small device size (∼1 m). The pre-ionization technique using the non-resonant heating produced the electron density in the order of 1017–1018 m−3 with the energy exceeds the CII ionization potential (30 eV). The existence of the relativistic electrons, which was essential to produce the seed plasmas, was confirmed experimentally during the pre-ionization phase by the synchrotron radiation and the hard x-ray emission measurements. The production mechanism of the relativistic electrons was considered to be stochastic interactions between the electrons and the microwave-frequency field. By optimizing the additional gas fueling during the microwave launch, a higher seed-plasma density more than 4 × 1018 m−3 was obtained, resulting that a rapid density evolution after NBI turn-on was successful even in the low NBI power (0.3 MW) condition. The seed plasmas produced by the pre-ionization method is useful to realize the plasma start-up under low absorption power condition in larger heliotron/stellarator devices such as perpendicular NBI in W7-X or deuterium NBI in LHD. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
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26. RNAcentral: A comprehensive database of non-coding RNA sequences

Author

Petrov, AI, Kay, SJE, Kalvari, I, Howe, KL, Gray, KA, Bruford, EA, Kersey, PJ, Cochrane, G, Finn, RD, Bateman, A, Kozomara, A, Griffiths-Jones, S, Frankish, A, Zwieb, CW, Lau, BY, Williams, KP, Chan, PP, Lowe, TM, Cannone, JJ, Gutell, RR, Machnicka, MA, Bujnicki, JM, Yoshihama, M, Kenmochi, N, Chai, B, Cole, JR, Szymanski, M, Karlowski, WM, Wood, V, Huala, E, Berardini, TZ, Zhao, Y, Chen, R, Zhu, W, Paraskevopoulou, MD, Vlachos, IS, Hatzigeorgiou, AG, Ma, L, Zhang, Z, Puetz, J, Stadler, PF, McDonald, D, Basu, S, Fey, P, Engel, SR, Cherry, JM, Volders, PJ, Mestdagh, P, Wower, J, Clark, M, Quek, XC, Dinger, ME, Petrov, AI, Kay, SJE, Kalvari, I, Howe, KL, Gray, KA, Bruford, EA, Kersey, PJ, Cochrane, G, Finn, RD, Bateman, A, Kozomara, A, Griffiths-Jones, S, Frankish, A, Zwieb, CW, Lau, BY, Williams, KP, Chan, PP, Lowe, TM, Cannone, JJ, Gutell, RR, Machnicka, MA, Bujnicki, JM, Yoshihama, M, Kenmochi, N, Chai, B, Cole, JR, Szymanski, M, Karlowski, WM, Wood, V, Huala, E, Berardini, TZ, Zhao, Y, Chen, R, Zhu, W, Paraskevopoulou, MD, Vlachos, IS, Hatzigeorgiou, AG, Ma, L, Zhang, Z, Puetz, J, Stadler, PF, McDonald, D, Basu, S, Fey, P, Engel, SR, Cherry, JM, Volders, PJ, Mestdagh, P, Wower, J, Clark, M, Quek, XC, and Dinger, ME

Abstract

© The Author(s) 2016. RNAcentral is a database of non-coding RNA (ncRNA) sequences that aggregates data from specialised ncRNA resources and provides a single entry point for accessing ncRNA sequences of all ncRNA types from all organisms. Since its launch in 2014, RNAcentral has integrated twelve new resources, taking the total number of collaborating database to 22, and began importing new types of data, such as modified nucleotides from MODOMICS and PDB. We created new species-specific identifiers that refer to unique RNA sequences within a context of single species. The website has been subject to continuous improvements focusing on text and sequence similarity searches as well as genome browsing functionality. All RNAcentral data is provided for free and is available for browsing, bulk downloads, and programmatic access at http://rnacentral.org/.

Published
2017

27. Major results from the first plasma campaign of the Wendelstein 7-X stellarator

Author

Wolf, R.C., Ali, A., Alonso, A., Baldzuhn, J., Beidler, C., Beurskens, M., Biedermann, C., Bosch, H.S., Bozhenkov, S., Brakel, R., Dinklage, A., Feng, Y., Fuchert, G., Geiger, J., Grulke, O., Helander, P., Hirsch, M., Höfel, U., Jakubowski, M., Knauer, J., Kocsis, G., König, R., Kornejew, P., Kràmer-Flecken, A., Krychowiak, M., Landreman, M., Langenberg, A., Laqua, H. P., Lazerson, S., Maaßberg, H., Marsen, S., Marushchenko, M., Moseev, D., Niemann, H., Pablant, N., Pasch, E., Rahbarnia, K., Schlisio, G., Stange, T., Sunn Pedersen, T., Svensson, J., Szepesi, T., Trimino Mora, H., Turkin, Y., Wauters, T., Weir, G., Wenzel, U., Windisch, T., Wurden, G., Zhang, D., Abramovic, I., Äkàslompolo, S., Aleynikov, P., Aleynikova, K., Alzbutas, R., Anda, G., Andreeva, T., Ascasibar, E., Assmann, J., Baek, S. G., Banduch, M., Barbui, T., Barlak, M., Baumann, K., Behr, W., Benndorf, A., Bertuch, O., Biel, W., Birus, D., Blackwell, B., Blanco, E., Blatzheim, M., Bluhm, T., Böckenhoff, D., Bolgert, P., Borchardt, M., Borsuk, V., Boscary, J., Böttger, L. G., Brand, H., Brandt, Ch, Bràuer, T., Braune, H., Brezinsek, S., Brunner, K. J., Brünner, B., Burhenn, R., Buttenschön, B., Bykov, V., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chernyshev, F., Cianciosa, M., Citarella, R., Ciupiński, Claps, G., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czermak, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., Dammertz, G., Danielson, J., De La Pena, A., Degenkolbe, S., Denner, P., Dhard, D. P., Dostal, M., Drevlak, M., Drewelow, P., Drews, Ph, Dudek, A., Dundulis, G., Durodie, F., Van Eeten, P., Effenberg, F., Ehrke, G., Endler, M., Ennis, D., Erckmann, E., Esteban, H., Estrada, T., Fahrenkamp, N., Feist, J. H., Fellinger, J., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Ford, O., Fornal, T., Frerichs, H., Freund, A., Führer, M., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Garcia-Munoz, M., Gates, D., Gawlik, G., Geiger, B., Giannella, V., Gierse, N., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Grosman, A., Grote, H., Gruca, M., Guerard, C., Haiduk, L., Han, X., Harberts, F., Harris, J. H., Hartfuß, H. J., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Heitzenroeder, P., Henneberg, S., Hennig, C., Hernandez Sanchez, J., Hidalgo, C., Hölbe, H., Hollfeld, K. P., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huber, M., Huber, V., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Ivanov, A., Jablonski, S., Jagielski, J., Jelonnek, J., Jenzsch, H., Junghans, P., Kacmarczyk, J., Kaliatka, T., Kallmeyer, J. P., Kamionka, U., Karalevicius, R., Kasahara, H., Kasparek, W., Kenmochi, N., Keunecke, M., Khilchenko, A., Kinna, D., Kleiber, R., Klinger, T., Knaup, M., Kobarg, Th, Köchl, F., Kolesnichenko, Y., Könies, A., Köppen, M., Koshurinov, J., Koslowski, R., Köster, F., Koziol, R., Krämer, M., Krampitz, R., Kraszewsk, P., Krawczyk, N., Kremeyer, T., Krings, Th, Krom, J., Krzesinski, G., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kwak, S., Lang, R., Langish, S., Laube, R., Lechte, C., Lennartz, M., Leonhardt, W., Lewerentz, L., Liang, Y., Linsmeier, Ch, Liu, S., Lobsien, J. F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lubyako, L., Lücke, A., Lumsdaine, A., Lutsenko, V., Majano-Brown, J., Marchuk, O., Mardenfeld, M., Marek, P., Massidda, S., Masuzaki, S., Maurer, D., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, Ph, Mikkelsen, D., Mishchenko, O., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morizaki, T., Munk, R., Murakami, S., Musielok, F., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neubauer, O., Neuner, U., Ngo, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Pan, W., Panadero, N., Panadero Alvarez, N., Panin, A., Papenfuß, D., Paqay, S., Pavone, A., Pawelec, E., Pelka, G., Peng, X., Perseo, V., Peterson, B., Pieper, A., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Povilaitis, M., Preinhaelter, J., Proll, J., Puiatti, M. E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Rimkevicius, S., Riße, K., Rodatos, A., Röhlinger, H., Romé, M., Rong, P., Roscher, H. J., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Samartsev, A., Sanchez, M., Sano, F., Satake, S., Satheeswaran, G., Schacht, J., Schauer, F., Scherer, T., Schlaich, A., Schlüter, K. H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, M., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Shanahan, B., Shikhovtsev, I. V., Sibilia, M., Sinha, P., Siplià, S., Skodzik, J., Slaby, C., Smith, H., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Standley, B., Stephey, L., Stoneking, M., Stridde, U., Sulek, Z., Surko, C., Suzuki, Y., Szabó, V., Szabolics, T., Szökefalvi-Nagy, Z., Tamura, N., Terra, A., Terry, J., Thomas, J., Thomsen, H., Thumm, M., Von Thun, C. P., Timmermann, D., Titus, P., Toi, K., Travere, J. M., Traverso, P., Tretter, J., Tsuchiya, H., Tsujimura, T., Tulipán, S., Turnyanskiy, M., Unterberg, B., Urban, J., Urbonavicius, E., Vakulchyk, I., Valet, S., Van Millingen, B., Vela, L., Velasco, J. L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Vorkörper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Warmer, F., Wegener, L., Weggen, J., Wei, Y., Wendorf, J., Werner, A., Wiegel, B., Wilde, F., Winkler, E., Winters, V., Wolf, S., Wolowski, J., Wright, A., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zajac, J., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zimbal, A., Zocco, A., Zoletnik, S., Zuin, M., Wolf, R.C., Ali, A., Alonso, A., Baldzuhn, J., Beidler, C., Beurskens, M., Biedermann, C., Bosch, H.S., Bozhenkov, S., Brakel, R., Dinklage, A., Feng, Y., Fuchert, G., Geiger, J., Grulke, O., Helander, P., Hirsch, M., Höfel, U., Jakubowski, M., Knauer, J., Kocsis, G., König, R., Kornejew, P., Kràmer-Flecken, A., Krychowiak, M., Landreman, M., Langenberg, A., Laqua, H. P., Lazerson, S., Maaßberg, H., Marsen, S., Marushchenko, M., Moseev, D., Niemann, H., Pablant, N., Pasch, E., Rahbarnia, K., Schlisio, G., Stange, T., Sunn Pedersen, T., Svensson, J., Szepesi, T., Trimino Mora, H., Turkin, Y., Wauters, T., Weir, G., Wenzel, U., Windisch, T., Wurden, G., Zhang, D., Abramovic, I., Äkàslompolo, S., Aleynikov, P., Aleynikova, K., Alzbutas, R., Anda, G., Andreeva, T., Ascasibar, E., Assmann, J., Baek, S. G., Banduch, M., Barbui, T., Barlak, M., Baumann, K., Behr, W., Benndorf, A., Bertuch, O., Biel, W., Birus, D., Blackwell, B., Blanco, E., Blatzheim, M., Bluhm, T., Böckenhoff, D., Bolgert, P., Borchardt, M., Borsuk, V., Boscary, J., Böttger, L. G., Brand, H., Brandt, Ch, Bràuer, T., Braune, H., Brezinsek, S., Brunner, K. J., Brünner, B., Burhenn, R., Buttenschön, B., Bykov, V., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chernyshev, F., Cianciosa, M., Citarella, R., Ciupiński, Claps, G., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czermak, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., Dammertz, G., Danielson, J., De La Pena, A., Degenkolbe, S., Denner, P., Dhard, D. P., Dostal, M., Drevlak, M., Drewelow, P., Drews, Ph, Dudek, A., Dundulis, G., Durodie, F., Van Eeten, P., Effenberg, F., Ehrke, G., Endler, M., Ennis, D., Erckmann, E., Esteban, H., Estrada, T., Fahrenkamp, N., Feist, J. H., Fellinger, J., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Ford, O., Fornal, T., Frerichs, H., Freund, A., Führer, M., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Garcia-Munoz, M., Gates, D., Gawlik, G., Geiger, B., Giannella, V., Gierse, N., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Grosman, A., Grote, H., Gruca, M., Guerard, C., Haiduk, L., Han, X., Harberts, F., Harris, J. H., Hartfuß, H. J., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Heitzenroeder, P., Henneberg, S., Hennig, C., Hernandez Sanchez, J., Hidalgo, C., Hölbe, H., Hollfeld, K. P., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huber, M., Huber, V., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Ivanov, A., Jablonski, S., Jagielski, J., Jelonnek, J., Jenzsch, H., Junghans, P., Kacmarczyk, J., Kaliatka, T., Kallmeyer, J. P., Kamionka, U., Karalevicius, R., Kasahara, H., Kasparek, W., Kenmochi, N., Keunecke, M., Khilchenko, A., Kinna, D., Kleiber, R., Klinger, T., Knaup, M., Kobarg, Th, Köchl, F., Kolesnichenko, Y., Könies, A., Köppen, M., Koshurinov, J., Koslowski, R., Köster, F., Koziol, R., Krämer, M., Krampitz, R., Kraszewsk, P., Krawczyk, N., Kremeyer, T., Krings, Th, Krom, J., Krzesinski, G., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kwak, S., Lang, R., Langish, S., Laube, R., Lechte, C., Lennartz, M., Leonhardt, W., Lewerentz, L., Liang, Y., Linsmeier, Ch, Liu, S., Lobsien, J. F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lubyako, L., Lücke, A., Lumsdaine, A., Lutsenko, V., Majano-Brown, J., Marchuk, O., Mardenfeld, M., Marek, P., Massidda, S., Masuzaki, S., Maurer, D., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, Ph, Mikkelsen, D., Mishchenko, O., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morizaki, T., Munk, R., Murakami, S., Musielok, F., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neubauer, O., Neuner, U., Ngo, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Pan, W., Panadero, N., Panadero Alvarez, N., Panin, A., Papenfuß, D., Paqay, S., Pavone, A., Pawelec, E., Pelka, G., Peng, X., Perseo, V., Peterson, B., Pieper, A., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Povilaitis, M., Preinhaelter, J., Proll, J., Puiatti, M. E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Rimkevicius, S., Riße, K., Rodatos, A., Röhlinger, H., Romé, M., Rong, P., Roscher, H. J., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Samartsev, A., Sanchez, M., Sano, F., Satake, S., Satheeswaran, G., Schacht, J., Schauer, F., Scherer, T., Schlaich, A., Schlüter, K. H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, M., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Shanahan, B., Shikhovtsev, I. V., Sibilia, M., Sinha, P., Siplià, S., Skodzik, J., Slaby, C., Smith, H., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Standley, B., Stephey, L., Stoneking, M., Stridde, U., Sulek, Z., Surko, C., Suzuki, Y., Szabó, V., Szabolics, T., Szökefalvi-Nagy, Z., Tamura, N., Terra, A., Terry, J., Thomas, J., Thomsen, H., Thumm, M., Von Thun, C. P., Timmermann, D., Titus, P., Toi, K., Travere, J. M., Traverso, P., Tretter, J., Tsuchiya, H., Tsujimura, T., Tulipán, S., Turnyanskiy, M., Unterberg, B., Urban, J., Urbonavicius, E., Vakulchyk, I., Valet, S., Van Millingen, B., Vela, L., Velasco, J. L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Vorkörper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Warmer, F., Wegener, L., Weggen, J., Wei, Y., Wendorf, J., Werner, A., Wiegel, B., Wilde, F., Winkler, E., Winters, V., Wolf, S., Wolowski, J., Wright, A., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zajac, J., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zimbal, A., Zocco, A., Zoletnik, S., and Zuin, M.

Abstract

After completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning the device, first plasma operation started at the end of 2015. Integral commissioning of plasma start-up and operation using electron cyclotron resonance heating (ECRH) and an extensive set of plasma diagnostics have been completed, allowing initial physics studies during the first operational campaign. Both in helium and hydrogen, plasma breakdown was easily achieved. Gaining experience with plasma vessel conditioning, discharge lengths could be extended gradually. Eventually, discharges lasted up to 6 s, reaching an injected energy of 4 MJ, which is twice the limit originally agreed for the limiter configuration employed during the first operational campaign. At power levels of 4 MW central electron densities reached 3 1019 m-3, central electron temperatures reached values of 7 keV and ion temperatures reached just above 2 keV. Important physics studies during this first operational phase include a first assessment of power balance and energy confinement, ECRH power deposition experiments, 2nd harmonic O-mode ECRH using multi-pass absorption, and current drive experiments using electron cyclotron current drive. As in many plasma discharges the electron temperature exceeds the ion temperature significantly, these plasmas are governed by core electron root confinement showing a strong positive electric field in the plasma centre.

Published
2017

29. RNAcentral: a comprehensive database of non-coding RNA sequences

Author

Petrov, AI, Kay, SJE, Kalvari, I, Howe, KL, Gray, KA, Bruford, EA, Kersey, PJ, Cochrane, G, Finn, RD, Bateman, A, Kozomara, A, Griffiths-Jones, S, Frankish, A, Zwieb, CW, Lau, BY, Williams, KP, Chan, PP, Lowe, TM, Cannone, JJ, Gutell, RR, Machnicka, MA, Bujnicki, JM, Yoshihama, M, Kenmochi, N, Chai, B, Cole, JR, Szymanski, M, Karlowski, WM, Wood, V, Huala, E, Berardini, TZ, Zhao, Y, Chen, R, Zhu, W, Paraskevopoulou, MD, Vlachos, IS, Hatzigeorgiou, AG, Ma, L, Zhang, Z, Puetz, J, Stadler, PF, McDonald, D, Basu, S, Fey, P, Engel, SR, Cherry, JM, Volders, PJ, Mestdagh, P, Wower, J, Clark, M, Quek, XC, Dinger, ME, Bruford, Elspeth [0000-0002-8380-5247], Wood, Valerie [0000-0001-6330-7526], and Apollo - University of Cambridge Repository

Subjects
EXPRESSION, 0301 basic medicine, RNA, Untranslated, MICRORNAS, Sequence analysis, Genomics, Context (language use), Biology, computer.software_genre, Data type, Genome, 03 medical and health sciences, Species Specificity, TARGETS, RESOURCE, REVEALS, TRANSCRIPTS, Genetics, Database Issue, Animals, Humans, GENOME DATABASE, LANDSCAPE, Database, Nucleotides, Sequence Analysis, RNA, Biology and Life Sciences, Subject (documents), Non-coding RNA, GENE DATABASE, Identifier, 030104 developmental biology, UPDATE, Databases, Nucleic Acid, computer
Abstract

RNAcentral is a database of non-coding RNA (ncRNA) sequences that aggregates data from specialised ncRNA resources and provides a single entry point for accessing ncRNA sequences of all ncRNA types from all organisms. Since its launch in 2014, RNAcentral has integrated twelve new resources, taking the total number of collaborating database to 22, and began importing new types of data, such as modified nucleotides from MODOMICS and PDB. We created new species-specific identifiers that refer to unique RNA sequences within a context of single species. The website has been subject to continuous improvements focusing on text and sequence similarity searches as well as genome browsing functionality. All RNAcentral data is provided for free and is available for browsing, bulk downloads, and programmatic access at http://rnacentral.org/.

Published
2016

30. Preface (Special issue on Analysis of non-equilibrium evolution problems: selected topics in material and life sciences)

Author

Aiki, T., Hulshof, J., Kenmochi, N., Muntean, A., Center for Analysis, Scientific Computing & Appl., and Applied Analysis

Abstract

The more one dives into the structural details of material or life sciences problems, the more sophisticated and specific the mathematical tools needed to address these problems become. The challenges are generally twofold: On the one hand one wishes to find accurate descriptions of the microscale, while on the other hand, having in view certain microscale dynamics (close to micro phase transitions), one wishes to capture a basic understanding over much larger scales. In both cases one aims at well-posed PDE models in the sense of Hadamard, which are not only computable numerically but also verifiable against experiments.

Published
2014

31. On the asymptotic behaviour of the p-Laplace equation in cylinders becoming unbounded

Author

Kenmochi, N, Ôtani, M, Zheng, S, Kenmochi, N ( N ), Ôtani, M ( M ), Zheng, S ( S ), Chipot, M, Xie, Y, Kenmochi, N, Ôtani, M, Zheng, S, Kenmochi, N ( N ), Ôtani, M ( M ), Zheng, S ( S ), Chipot, M, and Xie, Y

Abstract

In the rectangle Ωℓ = (−ℓ, ℓ) × (−1, 1), we consider the weak solution uℓ to the p-Laplace equation for a right hand side depending on x2 only. We show that, for any ℓ0 > 0, uℓ → u∞ in W 1,p(Ωℓ 0 ) when ℓ → ∞, where u∞ is the solution of the p-Laplace equation on the section.

Published
2004

32. On some problems in dimension two having a continuous free boundary

Author

Kenmochi, N, Kenmochi, N ( N ), Chipot, M, Kenmochi, N, Kenmochi, N ( N ), and Chipot, M

Abstract

We show that a large class of free boundary problems in dimension two have their free boundary defined by a continuous function. We mention some applications in particular to a quasilinear fluid flow problem.

Published
2000

33. Analysis and computations in the four-well problem

Author

Kenmochi, N, Niezgódka, M, Strzelecki, P, Kenmochi, N ( N ), Niezgódka, M ( M ), Strzelecki, P ( P ), Chipot, M, Lécuyer, V, Kenmochi, N, Niezgódka, M, Strzelecki, P, Kenmochi, N ( N ), Niezgódka, M ( M ), Strzelecki, P ( P ), Chipot, M, and Lécuyer, V

Published
1996

39. Detailed mapping, mutation analysis, and intragenic polymorphism identification in candidate Noonan syndrome genes MYL2, DCN, EPS8, and RPL6.

Author

Ion, A., Crosby, A., Kremer, J.M.J., Kenmochi, N., Reen, M.M.M. van, Fenske, C., Burgt, C.J.A.M. van der, Brunner, H.G., Montgomery, K., Kucherlapati, R.S., Patton, M.A., Page, D.C., Mariman, E.C.M., Jeffery, S., Ion, A., Crosby, A., Kremer, J.M.J., Kenmochi, N., Reen, M.M.M. van, Fenske, C., Burgt, C.J.A.M. van der, Brunner, H.G., Montgomery, K., Kucherlapati, R.S., Patton, M.A., Page, D.C., Mariman, E.C.M., and Jeffery, S.

Abstract

Item does not contain fulltext

Published
2000

40. Highly time-resolved evaluation technique of instantaneous amplitude and phase difference using analytic signals for multi-channel diagnostics.

Author

Ohshima, S., Kobayashi, S., Yamamoto, S., Nagasaki, K., Mizuuchi, T., Kado, S., Okada, H., Minami, T., Lee, H. Y., Zang, L., Kenmochi, N., Kasajima, K., Ohtani, Y., Shi, N., Nagae, Y., Konoshima, S., and Sano, F.

Subjects
SIGNALS & signaling, FLUCTUATIONS (Physics), AMPLITUDE modulation, PLASMA gas research, PLASMA diagnostics
Abstract

A fluctuation analysis technique using analytic signals is proposed. Analytic signals are suitable to characterize a single mode with time-dependent amplitude and frequency, such as an MHD mode observed in fusion plasmas since the technique can evaluate amplitude and frequency at a specific moment without limitations of temporal and frequency resolutions, which is problematic in Fourier-based analyses. Moreover, a concept of instantaneous phase difference is newly introduced, and error of the evaluated phase difference and its error reduction techniques using conditional/ensemble averaging are discussed. These techniques are applied to experimental data of the beam emission spectroscopic measurement in the Heliotron J device, which demonstrates that the technique can describe nonlinear evolution of MHD instabilities. This technique is widely applicable to other diagnostics having necessity to evaluate phase difference. [ABSTRACT FROM AUTHOR]

Published
2014
Full Text
View/download PDF

41. Interpretation of Plasma Fluctuation Data from Combination Measurement of a Perpendicular-View Camera and a Langmuir Probe in Heliotron J

Author

Zang, L., Mizuuchi, T., Nishino, N., Ohshima, S., Yamamoto, S., Sun, Y. C., Kasajima, K., Takeuchi, M., Mukai, K., Lee, H. Y., Kenmochi, N., Ohtani, Y., Nagasaki, K., Kado, S., Okada, H., Minami, T., Kobayashi, S., Shi, N., Konoshima, S., Nakamura, Y., and Sano, F.

Abstract

AbstractIn the medium-sized heliotron device Heliotron J, edge density fluctuation has been measured simultaneously with a high-speed video camera and a Langmuir probe. Poloidally propagating, parallel elongating filamentary structures with 20- to 30-kHz frequency and ~14-cm poloidal wavelength were observed by a camera. However, the radial position of this density mode is not well known with only camera data because the camera lens axis is perpendicular to the torus plane. To identify the span of this density mode, plasma-surface interaction (PSI) between the probe and the plasma has been analyzed. As the probe scanned into the plasma, enhanced brightness due to PSI was clearly observed in camera images. By comparing this enhanced brightness among different probe positions, the outmost margin of the 20- to 30-kHz mode observed by the camera has been identified to be within 10 mm outside from the last closed flux surface. This conclusion is supported by the spectrum of the probe data.

Published
2015
Full Text
View/download PDF

42. Calibrations of the LHD Thomson scattering system.

Author

Yamada, I., Funaba, H., Yasuhara, R., Hayashi, H., Kenmochi, N., Minami, T., Yoshikawa, M., Ohta, K., Lee, J. H., and Lee, S. H.

Subjects
THOMSON scattering, PHYSICAL measurements, ELECTRON temperature, CALIBRATION, FUSION (Phase transformation)
Abstract

The Thomson scattering diagnostic systems are widely used for the measurements of absolute local electron temperatures and densities of fusion plasmas. In order to obtain accurate and reliable temperature and density data, careful calibrations of the system are required. We have tried several calibration methods since the second LHD experiment campaign in 1998. We summarize the current status of the calibration methods for the electron temperature and density measurements by the LHD Thomson scattering diagnostic system. Future plans are briefly discussed. [ABSTRACT FROM AUTHOR]

Published
2016
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43. Development of beam emission spectroscopy for turbulence transport study in Heliotron J.

Author

Kobayashi, S., Ohshima, S., Matsuda, H., Lu, X. X., Kokubu, D., Ida, K., Kobayashi, T., Yoshinuma, M., Kado, S., Oishi, T., Nagasaki, K., Okada, H., Minami, T., Yamamoto, S., Nakamura, Y., Ishizawa, A., Kenmochi, N., Otani, Y., Konoshima, S., and Mizuuchi, T.

Subjects
EMISSION spectroscopy, SPECTRUM analysis, ATOMIC spectroscopy, SPECTROMETRY, FLUID dynamics
Abstract

This paper describes the development study of the beam emission spectroscopy (BES) for the turbulent transport study in Heliotron J. Modification of the sightlines (10 × 4 for edge and 10 × 2 for edge) enables us to obtain 2-dimensional BES imaging. The cooling effect on the reduction in the electrical noise of avalanche photodiode (APD) assembly has been investigated using a refrigerant cooling system. When the temperature of the APD element has set to be -20 °C, the electrical noise can be reduced more than 50%. The measurement error of the phase difference in the case of low signal level has been tested by two light-emitting diode lamps. The APD cooling has an effect to improve the measurement error at the low signal level of APD. [ABSTRACT FROM AUTHOR]

Published
2016
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44. A novel electron density reconstruction method for asymmetrical toroidal plasmas.

Author

Shi, N., Ohshima, S., Tanaka, K., Minami, T., Nagasaki, K., Yamamoto, S., Ohtani, Y., Zang, L., Mizuuchi, T., Okada, H., Kado, S., Kobayashi, S., Konoshima, S., Kenmochi, N., and Sano, F.

Subjects
ELECTRON density, CARRIER density, TOROIDAL plasma, PLASMA gases, SPHEROMAKS
Abstract

A novel reconstruction method is developed for acquiring the electron density profile from multichannel interferometric measurements of strongly asymmetrical toroidal plasmas. It is based on a regularization technique, and a generalized cross-validation function is used to optimize the regular-ization parameter with the aid of singular value decomposition. The feasibility of method could be testified by simulated measurements based on a magnetic configuration of the flexible helical-axis heliotron device, Heliotron J, which has an asymmetrical poloidal cross section. And the successful reconstruction makes possible to construct a multi-channel Far-infrared laser interferometry on this device. The advantages of this method are demonstrated by comparison with a conventional method. The factors which may affect the accuracy of the results are investigated, and an error analysis is carried out. Based on the obtained results, the proposed method is highly promising for accurately reconstructing the electron density in the asymmetrical toroidal plasma. [ABSTRACT FROM AUTHOR]

Published
2014
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45. Effect of supersonic molecular-beam injection on edge fluctuation and particle transport in Heliotron J.

Author

Zang, L., Ohshima, S., Mizuuchi, T., Nishino, N., Yamamoto, S., Kasajima, K., Hashimoto, K., Sha, M., Takeuchi, M., Mukai, K., Lee, H. Y., Kenmochi, N., Nagasaki, K., Kado, S., Okada, H., Minami, T., Kobayashi, S., Shi, N., Konoshima, S., and Nakamura, Y.

Subjects
MOLECULAR beams, BEAM injection, FLUCTUATIONS (Physics), ENERGY storage, GAUSSIAN beams, PHASE transitions
Abstract

Edge fluctuation in a supersonic molecular-beam injection (SMBI) fueled plasma has been measured using an electrostatic probe array. After SMBI, the plasma stored energy (Wp) temporarily decreased then started to increase. The local plasma fluctuation and fluctuation induced particle transport before and after SMBI have been analyzed. In a short duration (4 ms) just after SMBI, the density fluctuation of broad-band low frequency increased, and the probability density function (PDF) changed from a nearly Gaussian to a positively skewed non-Gaussian one. This suggests that intermittent structures were produced due to SMBI. Also the fluctuation induced particle transport was greatly enhanced during this short duration. About 4ms after SMBI, the low frequency broad-band density fluctuation decreased, and the PDF returned to a nearly Gaussian shape. Also the fluctuation induced particle transport was reduced. Compared with conventional gas puff, Wp degradation window is very short due to the short injection period of SMBI. After this short degradation window, fluctuation induced particle transport was reduced and Wp started the climbing phase. Therefore, the short period of the influence to the edge fluctuation might be an advantage of this novel fueling technique. On the other hand, although their roles are not identified at present, coherent MHD modes are also suppressed as well by the application of SMBI. These MHD modes are thought to be de-exited due to a sudden change of the edge density and/or excitation conditions. [ABSTRACT FROM AUTHOR]

Published
2014
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46. Publisher's Note: "Study of detached plasma profile in the divertor simulation experimental module of tandem mirror GAMMA 10/PDX" [AIP Advances 11, 125231 (2021)].

Author

Yoshikawa, M., Kohagura, J., Ezumi, N., Iijima, T., Nojiri, K., Terakado, A., Nakashima, Y., Kariya, T., Numakura, T., Hirata, M., Minami, R., Sakamoto, M., Ichimura, M., Islam, M. S., Shima, Y., Yasuhara, R., Yamada, I., Funaba, H., Minami, T., and Kenmochi, N.

Subjects
PUBLISHING, TRAFFIC cameras
Published
2022
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48. First measurement of time evolution of electron temperature profiles with Nd:YAG Thomson scattering system on Heliotron J.

Author

Kenmochi, N., Minami, T., Takahashi, C., Tei, S., Mizuuchi, T., Kobayashi, S., Nagasaki, K., Nakamura, Y., Okada, H., Kado, S., Yamamoto, S., Ohshima, S., Konoshima, S., Shi, N., Zang, L., Ohtani, Y., Kasajima, K., and Sano, F.

Subjects
*THOMSON scattering, *ELECTRON temperature, *ELECTROMAGNETIC wave scattering, *POLYCHROMATORS, *PLASMA gas research
Abstract

A Nd:YAG Thomson scattering system has been developed for Heliotron J. The system consists of two 550 mJ 50 Hz lasers, large collection optics, and 25 radial channel (~1 cm spatial resolution) interference polychromators. This measurement system achieves a S/N ratio of ~50 for low-density plasma (ne 0.5 x 1019 m-3). A time evolution of electron temperature profiles was measured with this system for a high-intensity gas-puff (HIGP) fueling neutral-beam-injection plasma. The peripheral temperature of the higher-density phase after HIGP recovers to the low-density pre-HIGP level, suggesting that improving particle transport in the HIGP plasma may be possible. [ABSTRACT FROM AUTHOR]

Published
2014
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